If you are playing a team with so/fr guards and very good lp players would pressure the guards with a plus def or a minus to shut down the post and make the guards beat you

Depends on where the other team scores from, how good your post defenders are, etc.  If they score inside, I would probably play a -1 or -2. If you aren't playing a press, you might be able to doubleteam a weak BH/P guard to create turnovers.

I would not double team anyone who wasn't the primary scorer, ever. Agreed that it depends where their scoring comes from, but I'd expect that the kind of team you described got most of its scoring from the very good interior players, in which case I'd be playing a minus defense.

EDIT: Looks like you played a -3, which is what I would've opted for, and defended them quite well but lost the game with a rough offensive effort.

grit25, yeah i was disappointed in my O. They are a good defensive team but i thought i would shut them down abit more than occured.