I've been deer hunting with muzzle loaders for decades and here are the main things I'd suggest:
- Get a stainless steel model, muzzle loaders are dirty and need to be cleaned often.
- Get a break open breech model that has an easy to remove breech plug so it is easy to clean.
- Get one that uses 12ga shotgun primers as the cap.
- Set it up with a scope and any quality variable scope in the 2X to 10X max magnification range.
- Get a 50 cal.
- Use (2) 50gr pellets -vs- powder. I like Triple 7 pellets.
- Use a bullet with plastic sabot such as Hornady.
- Put a sling on it.
- Get some speed loaders to carry a couple charges, bullets and caps in the field so you can reload a second shot pretty quick.
I'd stay away from that Nitrofire that requires using those fire stick charges and get something that simply uses loose powder or pellets.
In my opinion that CVA Optima is a pretty nice gun.
When you sight in off the bench, clean between every shot. It's slow and tedious, but you will be hunting with a clean barrel so need to sight it in that way. Try different bullets and powder charges till you find what it likes.
Any of the muzzle loaders with an easily removable breech plug can be quickly unloaded by pulling the plug and letting the pellets fall out, then tap the bullet thru with the ramrod.
Just out of curiosity ...... Why are you going back and forth between crossbow and muzzle loader and not considering a modern centerfire rifle or shotgun? Either would be a much more efficient weapon.
Good luck !