Retractable shoulder harness? & Reaching the FLap Handle

I'm having problems reaching the flap handle in my 170 when pulling it from 0-10 degrees. I'm not short by any means, 5'11".
I have to have my shoulder harnesses as loose as possible in order to reach the flap handle when it's on the floor. The maxed out length of the shoulder harness even slipped through the bracket and came undone once—sketchy.
My plane even came with an STC'd extension handle to make it easier to reach, but it feels quite crap and is large and in the way.
I'm wondering about installing a retractable portion of the shoulder harness, similar to a car. Can anyone give me suggestions on a specific model? Obviously, not looking to break the bank with this one but it certainly compromises safety the way I have it.
I have to have my shoulder harnesses as loose as possible in order to reach the flap handle when it's on the floor. The maxed out length of the shoulder harness even slipped through the bracket and came undone once—sketchy.
My plane even came with an STC'd extension handle to make it easier to reach, but it feels quite crap and is large and in the way.
I'm wondering about installing a retractable portion of the shoulder harness, similar to a car. Can anyone give me suggestions on a specific model? Obviously, not looking to break the bank with this one but it certainly compromises safety the way I have it.