Low variance slot machines

I have a very positive promotion and want to know what the lowest variance slot machines are so I can play a long time without losing quickly as the promotion will push me far into the positive but don't want to be down $500 all the time.Should I play 5 ,10,25 cent or $1,$5........I have a $1 machine that pays almost 99% but the variance is still big and can be down $500-$1000 before winning most of it back.Should I just play the old 3reel non progressives?
thanks and I hope someone knows the best low volatility machines.

You'll see the best bang for your buck on the simple, single line machines, and although chances are better at hitting jackpots at the higher denominations, if being down $1000 is a problem for you then you might not want to play above the quarter level. I always look at slots as BEASTS, and you're only hope most of the time is to out-beast them with bankroll.