question about running nolvadex right before my contest

Ok, so I'm getting to the point where I'm about to start dropping compounds before the show. I dropped the prop and suspension yesterday, just under 3 wks out(I ran out, would have run it to 10-14 days out if I could) and next week I will drop my EQ, then continue to run the tren to 5 days out, the winny 3 or 4 days out, masteron and var straight through show. My question is concerning the estrogen rebound many get from dropping test. I was planning on doing 40mg nolva ed but that was if I could have run the test 10-14 days out. I only have like 10, 20mg nolva tabs on hand, I'll probably have to order some liquid stuff really soon. Could I get by with just running 20mg/day for the next wk and a half, then bumping it up to 30-40mg as the show gets closer to shed water? I guess what I'm asking is how crucial is it to bump my nolva up now as opposed to a week later?