5 man multiboxing

I am very new to multiboxing as a whole, but I was just wondering what the setup would be like for multiboxing with 5 toons.

Would it be advantageous to set up cast sequences, or to set up each skill on, say, 1 2 3 etc for each toon? The only problem I have with cast sequences are things like the warrior class, based on rage gained and rage spent. It is entirely possible when using a cast sequence each warrior may not have the same amount of rage by the end of the sequence. What then? I would like to role with 1 tank, 1 heals, and 3 dps so I can que up for dungeons without any need for a 90 to come and help me along and I would also like to run with different classes.

Should I set up anything in ISBoxer to help me with the process?

[MiRai]

Would it be advantageous to set up cast sequences, or to set up each skill on, say, 1 2 3 etc for each toon?

Ultimately, that's up to you. Whichever route (castsequence vs spamming keys) works best for the team composition you're using (as well as your personal playstyle).

Should I set up anything in ISBoxer to help me with the process?

When people move to mixed-class teams we usually recommend taking a look at the Pro System.

After watching the video, I ultimately come down to two problems.

1:
Based on what the video describes, my healer would only heal the tank. How would I be able to set it up where the healer would target and heal the toon with the least health and/or dispel curses so that I wouldn't have to worry about my DPS/heals dying on me?
2:
So, with my experience multiboxing 3 toons, it seems I am just fine with the melee attacking the enemy, as IWT moves the melee within the correct distance AND faces them in the right direction. Now, is it possible to not necessarily move casters within melee range, BUT make them face the correct direction? I always seem to have problems with my Mage not wanting to cast frostbolt or whatever simply because he was attacking something in front of him, killed it, and the next enemy is behind him.

[MiRai]

Based on what the video describes, my healer would only heal the tank.

I'll be honest, I haven't watched the video on the MMO Pro page for some time and I'm not in a position to re-watch it at the moment, but I'm pretty sure that Lax doesn't say you can only heal your tank. Healing, like most of multiboxing, comes down to your personal preference. You can use Click Bars, Menus, VideoFX, castsequences hard-coded to your party members, or some other method that you find that works for you -- This video might help give you some insight.

How would I be able to set it up where the healer would target and heal the toon with the least health and/or dispel curses so that I wouldn't have to worry about my DPS/heals dying on me?

ISBoxer can't make decisions for you and you're going to have to make those decisions yourself -- Multiboxing = mult-tasking.

So, with my experience multiboxing 3 toons, it seems I am just fine with the melee attacking the enemy, as IWT moves the melee within the correct distance AND faces them in the right direction. Now, is it possible to not necessarily move casters within melee range, BUT make them face the correct direction? I always seem to have problems with my Mage not wanting to cast frostbolt or whatever simply because he was attacking something in front of him, killed it, and the next enemy is behind him.

If you want to split up commands between certain sets of characters then you're going to need an Action Target Group; and here's a lesson on how to turn your characters during combat.

Alright, so after a bit of testing and frustration, I've decided to go with VIdeoFX as this is the best choice for me. So, after some configuring and getting Dxnothing setup, I've come to a problem where I absolutely have no idea why it is happening.

First off, I'm using 3 toons at the moment to give my self just some practice before jumping into 5-man. So, using ISboxer, I start off with pressing a hotkey which creates 2 Viewers and 3 Sources (the 2 viewers being for the 2 slave toons). However, I've decided to use another hotkey to switch to another toon, destroy the initial 2 viewers, and create 2 viewers for the master toon and the remaining slave toon. That switch is perfect, absolutely no problems occur. For clarification: lets say that my 3 toon's names are first, second, and third. Obviously, First would be the master toon meaning that he would start off with the bigger window, Second and Third being the smaller windows. The first time I switch windows, Second would have the larger window now and First and Third would appear at the bottom in smaller windows. However, when I switch to third, it likes to make First a smaller one, and Third a smaller one as well. It then takes me a couple switches to put everything back to normal, but as soon as I hit Third, it does it again. After that point, pretty much everything gets messed up.

I have the actions for switching to Third listed like this:
1. Switch to next toon.
2. First's Viewer Deleted
3. Second's Viewer Deleted
4. Third's Viewer Deleted (I added these 2 step's to ensure that the viewers were in fact deleted)
5. First's Viewer is created
6. Second's Viewer is created

Sorry for the long explanation, I wanted to make sure it made sense. Also, thank you for all your help.

After some playing around, and downloading the pastebin you provided in the video you linked, I've come up with a solution. I simply made separate keymaps, just as you did, destroying and creating the appropriate viewers, and assigning a keybind to each one. This is actually better than what I wanted because I'd personally rather not cycle through each one. All I've got to do now is setup my healing configuration...

Although, I would like to sincerely thank you for all the help and support you have provided me with. Your videos and advice have been a huge help for me in understanding these actions, VideoFX, and what ISboxer is capable of.