That's because;
1; you claim no money for a project so you try and mix and match parts.
2; You actually have the money but refuse to save for it and spend on mix and match parts.
3; This hobby is expensive no matter what you do. Saving $100 on spring or this and that equals 2 gas tanks filled?
Over the long run, it's peanuts.
Here is a tip for mixing and matching springs. Go to the Lunati web site or open up there catolog and search for your cam, find the soring(s) recommended for your cam and research there rates, installed heights and coil bind specs.
Then you can look through other places and view there specs to find a compatable Spring.
Happy hunting!