Need Some Advice With My Fatties

After my failed first attempt at making fatties, I figured I would clear up a few of my questions with the experts.

Can you cook them with different meats at the same time? I was getting requests from my family for ones rolled in sausage, ground turkey and ground beef. Will they cook similar or would it be better to stick with the same ground meat?

How long could I refridgerate a fully assembled fatty prior to cooking or does it matter? Going to cabin up north and I would rather assemble them at home and then bring them up in a cooler.

Last but not least, proir to the sky opening up and absolutely pouring on me during my last attempt, I found that they weren't coming up to temp very well. The smoker was holding between 260 and 300 for most of the smoke, with a few wild dips when the wind picked up. After 2 hours they were still sitting at around 145. Any ideas?

I know it's a lot, but my family isn't exactly as adventerous as I am when it comes to bbq experimentation, so I can't miss on my next attempt at fatties or I'm afraid they'll nix any further attempts.

Thanks for the help brethren!

Thanks for the tips! I'm a big proponent of the KISS method, so shouldn't be an issue keeping in line with that.

I was just as surprised that they weren't done, but I figured that it was just from the flex in the temps that slowed it down. I'll keep a better eye on it next time to make sure it's going right.

Oh, and I'm using a Masterbuilt gasser, the big fella XL. Not the best, but I manage.