Would this work with the small rig?
https://www.amazon.com/Adapter-NP-F970-Buckling-Blackmagic-Compatible/dp/B07LFCBQJ4/
Also, know of any cheaper side handles compatible with the smallrig?
For simplicity's sake you could just get this
https://www.amazon.com/gp/product/B07MMZRKWK/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
Uses the Weipu AC connector. I got one the other day and tested it out with some NPF970s and it does work. The screw connector on it is obnoxious and I swapped it for another bolt, but it's still an option that's not too bad. There are other brands selling these cheaper on Ebay too, but IDK if they're good or not.