probably an hr so of move time once they hit the temporary tank. since i have to move 2 Im thinking of moving all the fish to the 20 for a day or to maybe a week. i dont think i have time to do 2 in one day. or should I move all live stock at once to reduce stress?
You only need to drain the water, remove rocks or wood and remove fish. Everything else can be left in the tank, so just fill, add the rock/wood/fish and you're done.
It's fine to overstock for a short while, as long as you keep up good w/c.