was answered by Reiza in their forum (official support) no FFB clipping tool: this was the answer to FFB tool question existing?
"No.
And again, for G25 users since the introduction of "Low force boost" no need to set force in logitech control panel any higher then 100%. That WILL clip hig forces.
Set that to 100% and set low force boost to ~80%. That boosts lower forces while leaving high forces intact."