Gazza if you are both poling you will easily make more money
I only work with someone else on trad at the moment as my van is only set up for one, but even on trad i earn 50 % more than i normally do alone on a good day , i do that easily with someone doing the bottoms, and half of the extra makes his wage, the other extra is mine, its about £50 extra after wages
With wfp i would expect after a while for another lad to be doing pretty much the same as me, and so doing upto 100% more a day , so depending on your avg day rate yo will easily pay his wages and have some extra
The hard bit is making sure you get the extra work in , otherwise you will just be finishing by wednesday every week and losing money to wages!! So the days it frees up need to be for canvassing and new cleans till you are ful capacity for 2 guys