Most of those things you will pick up as you go, since every case is gonna be different. Sure, the 3401 has more power, but as long as you keep it flat, and you don't stay in one spot you will be ok.
For the most part the pads and products are gonna be the same, the main difference is that you will get it done faster, in less passes. As far as how much pressure to apply, if I remember correctly Mike has suggested about 25 lbs once the polish is broken, and for the last 2 passes no pressure on the machine.
If you can control the PCXP you can control the 3401, as I mention before, the main thing is to keep it flat on the paint or it will try to walk away from you... And to keep it flat.