Other legendary operators in the area are Island Lake Catskiing in Fernie. Island Lake Catskiing - Snowcat Boarding, Snow Cat Skiing in Canada
To get your feet wet though another option would be to come into Calgary and board at kpow for a couple days KPOW Fortress Mountain Cat Skiing | KPOW - Fortress Mountain CAT Skiiing
It's significantly cheaper than the alternates, and you can stay at a relatively cheap hotel in Calgary, or stay in Banff somewhere. Do a couple days there to get your legs under you, then maybe have a couple down days to check out the rockies, do the sightseeing thing, then head down to Island Lake, Baldface, Snowwater, etc.
I have ZERO experience with any of these places mind you, I'm just going off the thoughts of others on this.
I don't think you'd be in over your head as long as you're honest with the guides. Riding pure powder is technically easier than groomer/resort riding. The powder takes energy to compress under your feet, so you can actually run steeper lines on fresh powder without picking up too much speed. Cat/heli operators know that not everyone is going to be a pro, and they'll have sections of their mountains dedicated to the intermediate crowd.
Have fun I think you'll make all of us jealous!!!