-- Last Updated: Feb-20-13 11:01 AM EST --
I haven't glued kneeling pads into my boats. I use various foam pads from Bell or Cooke's Custom Sewing, and I just lay them on the bottom of the hull. Foam pads glued to the hull would get far too dirty and abraded in my boats - I can keep them and the boat a lot cleaner with removable pads. To keep them from slipping I install several "traction strips" on the hull. I find that the "indoor" variety of traction strip from 3-M works well (the outdoor variety needs to be "de-gritted" a bit because they are much more abrasive than what's necessary, and could potentially tear up your kneeling pad). To keep my knees from slipping forward on the pad in semi-severe paddling situations, I paint the knee area of the foam pad with "plastic dip" like what's used to coat tool handles. To keep my knees from slipping forward during much more severe paddling situations, I sewed a pair of canvas sleeves to the pad, one just ahead of each knee location, and inserted a short length of pool noodle into each sleeve. I find the sewn-in pool noodle to be a very solid support against knee-slippage, and the whole foam pad will not move under any circumstances with traction strips glued to the hull.
Obviously this type of outfitting would be less than ideal for really wild whitewater, but for what you describe it will be plenty good.