^ I've had to add 250ghs per mining rig to keep my payout the same at this score based pool. It now takes 2.5th to get 0.01 payout per BLOCK on slushes pool. I was running 4.5th(2.25th per rig) here to get 0.02 per BLOCK, now I've bumped it up to 5th to keep my total payout per BLOCK the same. The other pool I mine on has pplns payout so I keep my DAILY payout at 0.02. Ive had to add about the same ratio in ghs to keep a 0.02 payout per DAY at BTCguild. It now takes 1.25th there to get the 0.02 per DAY payout. It was only taking 1.1th before. Keeping my payouts at a certain amount by adding ghs(most of the time small, sometimes large) has worked very well for me. I also have some hosted miners, but I use a slightly different strategy with those.
Even if I wanted to keep adding miners I really couldn't unless I have an electrician put in a couple more circuits...$$$...not going to happen. I have miners in my garage, office, bonus room and crawlspace. The Mrs. would not stand for miners in the bedroom ;-)