Tool for removing valve springs.

Nothing that would really make it significantly better. Maybe a little bit different gusseting and I might make the jack screw thread on a pivot and then put a hemispherical dimple in the plate the carriage bolt sets on. That all comes from different designs that I’ve worked on in industry.
I rarely don’t fuss with purchased tools or equipment in quest to improve them or put my mark on them. Usually doesn’t make it any better, occasionally it does, and rare occasion I screw it up. Keeps me out of the bars.