My goal is to learn how to use kung fu grappling and I can't reach that by taking bjj. It's nothing against bjj. It's just me learning how to use my kung fu better and how to apply it against other fighting systems.
If you extract some grappling skill out of your CMA system, you may find out that since the information is not complete, it's very difficult to use those information as base and build your grappling skill on top of it. The grappling skill is much more than just a "shoot to the leg". For example,
How to
- apply the same throw from different angles?
- apply the same throw from different set up?
- counter a throw?
- change one throw into another?
- use kick, punch to set up your throw?
- develop your grip fighting skill?
- obtain a clinch ASAP?
- break away from a clinch?
- ...
You may just touch the skin of the grappling art this way. But you will never be able to get deeper into your grappling skill development. You may also develop some false confidence and think you can deal with Judo black belt or state level wrestlers.
Many years ago, a CMA school extracted some grappling skill out of their CMA system. That school sent 15 students to compete in one national level Shuai Chiao tournament. All 15 students lose. Since then that school has never sent any student to the grappling tournament. If you don't wrestle 15 rounds daily, it will be very difficult for your wrestling skill to work on the mat.
If you want to be a wrestler, you just have to train as a wrestler. You will also need a full knowledge to build your skill on. IMO, partial knowledge is just not enough.