Im adding a bathroom in my basement. This is in no way being inspected, but i want it to work correctly. There is an existing pump (that is rated for a bathroom) and tank that i put in for my washer. The tank is 24 feet of pipe away from where the toilet is going to go, but the 3" line coming out of the tank is only buried 12" down, to the bottom of the pipe. If i went the recommended 1/4 per foot, that would only leave me 6" to 90 up and put a flange on for the toilet. I believe i could get one of those short 90's to fit under there, but will i short 90 work? Or would i be better off going with a longer 90 and only going an 1/8 per foot?