Williams FP-H&R-TK with Gibb Lock Screw/Knob

[DCmauser]

A beginner here with Hardware question - I have the Williams fool proof FP-H&R-TK with target knobs on my H&R 1871 buffalo classic, and then I also got the Gibb Lock screw or knob from Brownells.  When tightened, the Gibb lock screw touches the barrel and there is even more room for further tightening that might tweak the front of aluminum sight base away from barrel.
Does this seem like a positive or repeatable set-up, or should I just shorten the screw or add a flat washer as a spacer?
I already broke a Chapman’s #90 bit, to torque the sight down real good.  I forgot where in FAQs or elsewhere that I saw link and discussion on Gibb lock screw from Brownells, but see another picture of it again from Dodd3-Bernie in an older FAQ topic related to long range sight for BC and target.  Help is appreciated.

[quickdtoo]

I'd just shorten the screw if it's too long. 

Tim

[DCmauser]

Thanks a lot, (as one might guess I'm not too mechanically inclined).

FYI - picture was on Reply #9 on following 2006 link, just two (2) clicks from FAQs:

http://www.gboreloaded.com/forums//index.php/topic,82250.msg503960.html

Thanks again.