I've been multi clienting for some time and, aside from the advice given above, I've adopted a few habits that seem to make life easier for me.
First, my laptop is a couple years old and, though it's specs well exceed minimum game recommendations, I've taken some steps to ensure it runs PW efficiently.
• Update to most current graphics driver
• Select "Windows Classic" in display personalization (takes less memory)
• Ensure EPW is the only program running
• Eliminate unnecessary background services
I typically multi client three alts; however, I've done as many as six in difficult instances without problems.
Second, and I do not claim to be an expert:
• I run the alt windows in cascaded mode -- easier for me to quickly select a particular window.
• From left to right, I always order the windows the same each day (muscle memory and all that)
• I always open the first window with Launcher, and this one is always my cleric. On my PC, this gives me one button at bottom of the screen for cleric, and a stack of buttons for the other alts. In a rush, I can alway click the "cleric" button if things get interesting.
• Finally, I always have my designated tank invite the other alts to party. That way, on my cleric's squad bar, the tank is always at the top, thereby making her just an instant easier to locate when I switch over.
With practice and a bit of forethought, I've found I can negotiate instances as efficiently as a more typical squad. On PWI I was doing BH69 daily with a barb and cleric and never experienced a squad wipe. Infact, I've never wiped in any instance since I began multi clienting -- my sin and archer doesn't steal aggro, and I'm wise enough to let my clerics tank magic bosses.
Aside from clerics, I've played venomancers more than any other class. I suspect it's a purely mental exercise, but I view my multi cliented squads from a veno's perspective -- cleric is my main, the other alts in squad are her "pets." Once the other alts are engaged with a boss, I switch to my cleric until the fight is over. This is just something that works for me.
Again, I don't pretend to be an expert, these are only some things that work for me.
