RLewis, it sounds like things are going nicely for your pond.
I don't recall the size of your pond or the stocking rates, but an unqualified response could be that there may not be a need to thin out the bream. This is of course assuming that you're not looking forward to cooking 'em up.
I think that with the bluegill at 4-6" and the LMB around 8", the LMB will certainly grow in length much faster then the bluegill, but the age group of LMB may never be able to eat their counterpart age group of bluegill, thus providing a solid brood stock year class of bluegill.
I'm not sure about when it would be best advised to try to fish for the LMB.
