I will try to answer a couple of the questions for you. Not true. Many guys use W209 primers and they work just fine. You won't have a problem using regular 209 primers, but that being said, when I did shoot 209 primers, I used muzzle loading specific ones, but only because that brands what I preferred. I'd have no problems shooting regular 209 primers.
I've never shot the White Hots so I can't comment on those. However, I have shot T7 and Pyrodex pellets. I know a lot of guys here don't like pellets, and they are more expensive, but honestly I prefer them when hunting. I just think they are much easier to deal with out in the field than loose powder. That said, I like the price of loose powder much better so I often shoot it at the range. I use Pyrodex pellets as they shot much better in my muzzle loader.

The other thing to try is BH209. If I had a gun that could shoot it, I'd probably be trying to it. It's a loose powder, and I wish they made in pellet form, but I think it would be worth dealing with loose powder to use BH209. It's so much cleaner. You don't have to worry about swabbing between shots or any of the other issues due to the dirtiness of black powder.
Do a search on this and you will find tons of information. That said, I've never shot a deer with any of the polymer tipped muzzle loader bullets, but I have shot a few with Power Belts, and I can tell you to avoid them. They are seriously the worst performing most overpriced muzzle loading item I've ever bought. I think many of us have tried them when we first started hunting only to realize later they sucked. Out of the group of guys I hunt with all but a couple of them have switched to something else, and the couple that haven't switched have the same problems year after year that the rest of us do, they just are too hard headed to switch, because these are what the guy at the store said to buy.

They do kill deer, but if you don't see where the deer falls, don't expect to find it. They very rarely pass through which results in a severe lack of blood trail. I found most of the deer I shot with them, but no thanks to a blood trail. I only had a blood trail on one of them. I shot it fairly close and hit bone. It left an entrance wound the size of a baseball and it did bleed. I don't know what happened to the bullet with that one. I was starting to get annoyed with the lack of blood trail, but after shooting one and seeing it fall over and start kicking, and then get up and run off and not being able to find it due to the lack of blood trail I finally had enough.

This is exactly the same experience each of my friends has had with them, and even with perfect shots deer have been very difficult to find. Looking online, it's also the exact experience many on here have had.

I'd personally avoid these. I switched to the Deep Curls and I love them. After using these I realized just how bad the Power Belts actually were. Not to mention the Deep Curls with Harvester Crush Rib Sabots are $25 for 50 bullets, and the Power Belts were $20 for 20 bullets. So I not only got a bullet that performs 10x better, but I also am paying half of the price for these.

If you want a good bullet, the Deep Curl is a great choice, but like I said the ones you are shooting may be great too. I can't really comment on them.