thanks 14U. the answers help hugely. I've been papertrading all in 100 share lots, which quickly ate up my limited cash. now I know I can keep some in reserve for setups and still have something in the market too if I want.
I had one last question I meant to ask last night but forgot:
How are you avoiding the roundtripping rule about buy/sell/buy or sell/buy/sell the same thing in short amount of time? Is it because you are only selling or buying % of the ETF total at any one time?