I replate inside a 10 gallon fish tank (fish not included). They cost $10. It's not as much room as I'd like, but I've managed ok.
I used to be very cautious with replating: I would wipe down the flasks and fish tank with a bleach solution for every replate and I used bleach and H2O2 as my sterilizing agents for my tools. It took a long time.
However, recently, I am trying to find the minimal requirements for sterility for time's sake. I still wipe down the inside of the fishtank, but usually just once beforehand. I should wipe the sides of the flasks with an alcohol soaked paper towel, but sometimes I am too impatient. I use bleach, H2O2, alcohol then fire on my tools, in that order. I use a camping stove (I know it says "Do not use indoors", but I only turn it on for 15 seconds at a time) for the flame. I, of course use latex gloves, for my skin more than anything else. I should use a dust mask to keep "wind" down, but I don't. I've been meaning to get some at the store, but always forget.
More than anything, I rely on speed and accuracy. The time from flask opening to flask closing is all that really matters aside from the other necessary precautions. If I'm concentrating, I have less than 1 in 20 go bad (often 100% success). If I'm just replating because I have to and I have 30 more to do and I'm tired & hungry, then the results are worse.