Sounds more like the 436 is suffering from simulcast distortion. The "dead zones" is a typical symptom when this is occurring. My old 436 did not do well with simulcast systems: it would work acceptably in some areas but be deaf only a short distance away. Putting "too much antenna" is actually the opposite of what you should do with this radio.
I agree simulcast is part of the problem, but the 436 performs relatively well on this system. I think his issue is probably sites. Depending where the OP is in Page, he may need to switch from the Page Site to Valley or vice-versa. A friend in Shenandoah has a Unication G4 that stays mainly on the Valley Site. I believe the farther north in Page, the Page site probably takes over coverage, but I don't know that for sure. With that being said, I have had my Unication pager lock onto the Page site when I was south of Elkton.
I don't have any issues obtaining the H/R & Page control channel with my 436. I would give the 436 an 8/10 for scanning this system. It does relatively well. The audio is a little overly-modulated and not 100% clear, due to simulcast. My 536 does have a little trouble obtaining the CC when mobile, but eventually gets it. It's not quite as clear as the 436. I have programmed the 352 and 996 for others, and they will totally miss some traffic with this system.