I'm about to buy one of the Optimizer Lite versions. I think I like the 5510, but would like to hear your thoughts on which one to get. Is the adjustable rheostat worth it, and am I right to want the .010 sight?

Yes, get the 0.010 with 6 ft fiber. Mine is the dial sight with 2" aperture and rheostat, and I love it. Won't shoot anything else now. Make sure that above all other things you get the 6 foot fiber and the rheostat
I got mine from bowhuntersuperstore.com they had the best deals.

Mine is the xl5500

What he said. I have one with and one with out. I prefer the one with for sure.

DS-5519 is what I have. I like the bigger pin size. I almost went with the .029, still kinda wish I had. I could do without the rheostat. I definitely like the smaller sized housing size vs the XL.

Yeah but your different driver!

I prefer the smaller aperture with a .019 pin. For hunting, the rheostat isn't absolutely necessary for me. And, I prefer the Kingpin model.

Ain't that the truth. Lol. We gotta do another trip one of these days.

I've got the KP-5519 with 0.10 pin. I've had issues with vision while hunting, couldn't resolve multiple pins, so I went with this. I was fortunate to have a friend nearby that let me try his early one morning at the crack of dawn. I was afraid that the small 0.10 pin would be difficult for me to see but the opposite was true. I also got the Blue Burst Light Kit ... this setup works extremely well for this old man with old eyes

Love the Rheostat too

Another thread here ... discusses pin size

The smaller housing is much easier to see through your peep. With the larger housing I cannot see the green ring to center my pin in the peep so I don't always shoot consistent if I rush. I have both and I'm more partial to the small housing with no rehostat (just a cover that screws in and out that does nothing in my opinion) and the .019 pin. I think it has 3' of fiber vs 6' on the larger and honestly I can't tell a difference as far as brightness goes.

Well y'all are all over the board!!!!

Whatever size peep you prefer should play a factor in the size housing you get IMO. I have a 1/4 in peep and it works perfect with the XL housing

Thank you. I have a larger peep to let all the light in that I can get and my peep wraps around that xl housing like a hugger on a beer. With the 3 foot fiber you may not need the rheostat but with my 6 ft if I don't put some shade on the fiber when the sun is out then my pin star bursts but in very very low light conditions I can slide the rheostat out and see my pin when most people are blinding themselves with a sight light or walking back to the truck.

Can I simply measure the inside aperture of my peep with a tape to determine what size it is? I "think" mine's a 1/4" (or would 3/16 be common?)....it's one of those blue G5 peeps I know.

I think mine is 3/16" Jeff. I will have to measure mine when I get home.

Got any drill bits? See which one fits....

I use a peep sight with a large aperture. I've never tried to line up my sight housing with my peep opening. The only thing that matters to me is putting my pin in the center of the peep. I never pay any attention to my level, either.

According to the drill bit test, mine is a 1/8th

Yeah, but you're weird.