First time rebuild problems-trouble upshifting

So after driving this thing around for awhile, Im not 100% happy with the shift quality.

At light/part throttle, the 1-2 shift is firm and deliberate, but not harsh. Exactly the way it should be. The part throttle 2-3 shift is very harsh and "snatchy". Kinda bangs into gear.

At heavy/full throttle, the 1-2 shift is kinda slow at first, like I can feel the kickdown band start to apply, and then the band fully applies somewhat suddenly and will chirp the tires. The 2-3 shift is absolutley perfect under full throttle.

If it makes any difference, I had to use a load controlled kickdown servo because my other one was missing a spring. I also did not block the accumulator.

Are there any tricks I can do to improve my full throttle 1-2 shift and the part throttle 2-3 shift?