If you use the stock Yamaha spring and the RRP spring stiffener everything just about falls together. Tried installing the Blowsion spring on my first RRP Handle pole several years ago - what a pain in the ass.
Note - remove the handle pole from the bracket and the handle pole bracket from the ski - reassemble on your bench with stock spring and reinstall on ski. Just did mine on my new hull and the whole process took about 30 min.