Brett,
I work with Wor Lass who does the bottoms traditionally and I WFP 'tops'.
I asked a similar question about working in pairs, with one half using a WFP some months back and was given some good advice (compliments of Steve K).
You have to think where you're starting point is going to be. For example if you do ten houses in one street, and one of them has a conservatory; start there.
Doing the tops generally won't affect the conservatory, which your mate can work on. As soon as you're done, go to the next house.
Hopefully by the time your mate has finished the first house, the drips will have stopped on the second.
Just stay ahead of him; which is no problem with a WFP versus a squeegie.
Sometimes I'm five houses ahead of Wor Lass and use radios to stay in contact (it makes her feel safer having them and I can find out where she is).
Another tip, when doing a load of houses in a street, is to spend five minutes depositing water barrels at strategic points (say one barrel for every four houses) before you start.
That way you don't even have to go back to your vehicle for more water.
Get your mate to pick the empty water barrels up as he follows you and deposit them in a centralised area for collection.
It's the small stuff that speeds you up.