I race Uni most of the time and I LOVE my deep boards. In medium wind I leave them down when going downwind, so no loss of time there at the A mark spin. set. When it's really blowing I'll pull them both half way up, but I've got the up line on them so I don't go to the leeward side to do it, just a quick pull on the line and up it comes. The only drawback is at the C mark or gate, I've got one more thing to do, put them both back down for the next upwind leg, so that does add a couple seconds, but I've never lost a race by -a couple seconds- so I don't think it really has an effect on my overall standings. ;^)

I do think the deeper boards will help you go better upwind (create more lift, point higher or sideslip less) and allow you to fly a hull earlier in medium wind, which also reduces drag, so that's a help.