Adding more weight isn't really helpful, but you need some draw. The last few strokes should be really light. Uphill, downhill, it should all be fine. With just the weight of the blade and a dulling razor you may end up with razor burn. The key, I think, is not to add the weight by torquing the edge of the razor into the strop, it'll bend/roll like that.

The stropping action occurs from the motion, not the pressure.

After a few years of practice you may notice that strokes with the nap of the leather require differing pressure than strokes against it, but thats really putting a lot of emphasis into the most simple steps of the straight shaving process.