You dont need or want to compress your bag. You want to lightly stuff it.
Compression sacks are usually heavy, several oz, and can ruin the bag eventually.
In a UL pack , the sleeping bag can provide shape and support for the pack bottom and a solid base to pack other gear on top of. Over-compressing it can prevent that. 17" is too long really though to go horizontal in bottom of most UL packs. A slightly larger dia and shorter length might be necessary to fit well in a pack.
I would get a cuben drybag, with the dia needed. That way its light , waterproof.