(Did a search on the forums about Light Touch, didn't found anything, apologies if this is a repost.)

I'm having a question about this, if i am wearing light armor, with a heavy helmet, the perk gets nullified?

Sorry, I couldn't find anything either but, if anyone has the Tunnel Runner perk on a character in the game, they might be able to check the effect by seeing if they move slower with a Heavy Helmet instead of a Light one. No guarantees the perks have the same rules that way but a pretty good indicator.