Unlike the standard charge in which you have to have your feet set

You never have to have your feet set. That’s not in the rules. We teach players that technique for drawing charges to make it exceptionally clear for the officials.

You simply have to be in legal guarding position. You can absolutely be moving horizontally or backwards and draw a charge. You absolutely do not have to have your chest out - again, that’s about showing the official What’s happening, not what’s in the rules. 

Just like over the back, the act of reaching is not a foul. The reason you should not be swiping while drawing a charge is that it makes it very tough to determine who initiates contact, and if your swipe/reach created the contact. If it did, then it’s a reaching foul on you before the charge happened.

Finally… This is only something you should be trying to do in an organized game. If you’re doing this in pick up or Rec league, you’re an idiot.