I feel everything on the bladder and cervix, but in my case, it's hands. He was head down at the u/s, and I can feel his head down there (hard and round) if I palpate - very very noticeable that it's a head. My placenta is on top, so I think that's why I don't feel much up top. Also, he's facing my back - not turned to the side or anything. So all the movement would be back there. Sometimes I think he turns diagonal or possibly transverse, and I get a bit of movement on the far side, but mostly, it's smack dab in the middle and way down low.
But if your baby IS breech, yeah, I'd definitely do the optimal positioning exercises now. Won't hurt to try! I really prefer my babies to be vertex early on, since my last one was a preemie, and preemies typically aren't considered good candidates for breech vaginal delivery. Thankfully, DS was in the perfect LOA vertex position when my water broke at 29 weeks, so he was a quick and easy vaginal birth - the doctors never even hinted at C-section, since he was positioned so well.