I use sweetmarias. I used their customer site for testing blends, then their commercial site to buy in bulk. They even have some entry level roasting stuff for sale, the only downfall with the popcorn roaster is if you roast too much in 1 day the plastic barrier melts a bit.

Mostly easy to roast, it gets difficult if you’re looking for an extremely light roast. I don’t have HVAC so I usually set up a couple of fans to blow the smoke out the window. The sweet spot for me is to stop when the beans are finishing their “first crack” and start to enter the “second crack”. There’s tons of YouTube/material on roasting with ovens or cheaper roasting guides.