@stuckinarut2 Hmmmm. We hate it when JWs use funerals as an opportunity to proselytize and recruit. Let's try not to take advantage of a wedding by doing the same for the dark side. In my opinion, just as funerals are no place for guileful witnessing, so should weddings not be a place for passive aggressive apostatizing. The occasion is strictly about the celebration of the person/couple in question :).
My only advice: Don't get drunk and belt the speech out like it's open mic night. That's not just for the Witnesses present, but something that might be appreciated by both the bride and the groom. A lucid, eloquent speech about your love for them beats a fraternity ramble about the boys, boys, boys.
Also, force of habit may see you resisting the urge to raise your glass in a manner that denotes a toast as you conclude your speech. There may be a chance that you COULD get away with the raised glass gesture, but try not to verbally instruct the audience to do so in like manner. Hopefully the unconscious act of mirroring will see the non-JWs raise their glasses in response.
Best wishes to the best man.