I spend a lot of time at Bear Creek, but I've never done the tubing. I also haven't been to Shawnee. So I wasn't going to bother responding (not very helpful, am I?) but I see you haven't received any responses.
I can just say that I've seen Bear's tubing from the lifts. Looks like nice, long runs. There are two of them. It gets quite busy when the conditions are good, so you need to book your time in advance.
That's all I have! BC is a nice place overall, but boy, the past 2 years it's been a real struggle to get snow on the ground. Fingers crossed that next year is better for them.