no point of doing that!
bigger pool = faster block solving but smaller shares
smaller pool = slower block solving but bigger shares
so each way you'l end up with same amount of earned coins.
so my advice, point your miners to same primary pool and.
Yeah I went through that scenario.
For example:
Primary in a day will find 3 blocks = .01...... per block
Back up in a day will find 8 blocks = .006.... per block
Number wise, a good number of days I come out better, than other days.