I am not saying 100 can replace or same as the 120 and obviously they have different plastic stiffness for 100/120/130 but I was just saying 100 can be “as close to” stiffer model for 145lbs person. I have both 100 and 120 tongue, green/blue/red/yellow spring that I played with on my 100. OP was worried that some boots maybe too stiff or too soft for certain situation, hence, being able to play around and testing it himself is the best way to get an idea.