I have never hunted Elk but have hunted with muzzleloaders for about 25 years. I am a traditionalist who carrys around a long flintlock with 2f black powder and a patched ball that I cast myself.
My friends that have evolved with modern smokepoling like Trip7 better than Pyrodex, they say it is a cleaner burning powder.
First thing you will want to do is check the State Regs! Find out what is and is not legal. Here in NY we could not use optics on Muzzleloaders until just a couple years ago. In PA they can only use flintlocks. I want to say I have heard that Colorado has some specific primitive regs also.
The powerbelt has a good following and that is a sign of a good bullet. The thing about any gun is you have to find the max powder with the smallest grouping. Just tossing more powder in does not a better shooter make. You will need to get a bunch of bullets and shoot off a bench. Start at around 100gr and clean and increase load by 50gr until you start loosing accuracy or the recoil becomes to much for you.
If I was an elk hunter I guess I could help more.