Was shooting yesterday and was having trouble centering my pin in my peep...so I began thinking how I could fix it...this is what I come up with and it works flawlessly. Fingernail polish.
I used to use the EXACT same thing, until I started using a hi-vis sight guard ring. Now, I just center the sight guard ring in the peep and good to go.
You should try lining your peep sight up with the ring on your sight housing. That way it's ALWAYS the same alignment. Then you just place your pin, where ever you want, not the peep, then the pin, together.