Soft Stepping / Shaft Length / Shaft Flex

thanks for your expertise. so technically if i were to discard the 3 iron head, i could soft step by installing each shaft in the next head down.

to be honest i just wanted to solve the nagging doubt in my head every time i addressed them that said -"these are stiffer, you're going to mess this shot up"

as you have both estimated the flex to be more or less equivalent i can blame myself entirely for any misfortunes.