Unless penis size is correlated with tongue strength (which I'm pretty sure it isn't...) it's not worth my trouble worrying about. The truth of the matter is, the penetrative aspect of sex (I think I just coined some new terminology...
) just isn't what it's all about for me. Also, I'm a lot more comfortable going down on a slightly smaller guy. I just don't have a big enough mouth... much to my own dissappointment.
I do enjoy larger men for hand jobs though. It's a little easier to get a good grip.