Tuning Hatsan flash 177, trying to get more shots

Hi, so i have a hatsan flash .177 that i would like to get some more shots out of, if possible, without the need to machine anything cause i don't have any tools for it and i am useless with them anyway. What i have done is to remove the 2 spacers that where in front of the hammerspring, and put a weaker valve spring in it, I read somewhere or saw some video of someone doing that to get a better curve, i don't know how many turns i have on the hammerspring and have not typed down every shot on the string, but my numbers are as follow in - 3c:

Jsb 10.34gr

Start: 190 bar

245 m/s (803,8 fps

10 shots 160 bar 246 m/s

20 shots 150 bar 254 m/s

30 shots 130+ bar 244 m/s

40 shots 110 bar 248 m/s

50 shots 100 bar 249 m/s

60 shots right under 100 bar 244

72 shots noticed last 2 shots going a little lower @ 35m 80 bar 232 m/s, so the speed was probably around 244 m/s for shot number 70. So i get 70 shots within 10 m/s spread, 244—254 m/s, 800,5 -833,3 fps, 30 fps spread, is that ok? Looking @ the start the gun uses 30 bar for 10 shots 190-160 bar, could i turn the hammerspring to improve that without getting bigger spread in speed, or should i just fill to 160 bar and use 60 shots between 160-80 bar?

Thank you and Merry Christmas!