That's a really cool build, well done! I'm wondering how you're using the trackball and mouse clicks. Do you use the trackball with your index and middle finger and have left and right mouse click on the thumb keys to press them with the thumb?
Yes I use the trackball with my index and middle finger and the 3 way thumb switch is mapped to left/middle/right mouse click. The trackpad is used for scrolling.
Most of the split kits are going to be around the same price. They start around 20. My Sofle kits were 25 each. You'd need to add a pair of MC's , switches, caps, which is where things get pricey. If you shop around you can find good deals. The PCBs and components represent a smaller part of the cost compared to the rest of the dressings.
I have no problem spending the money on a good setup I just don't have the funds to be able to jump right in spending like $300+ before I even know if I like the split setup
Would something like this be good to give the whole thing a try?
Kinesis Bluetooth Freestyle2 Ergonomic Keyboard for PC (20" Extended Separation) https://a.co/d/34ydGWq