I think people overreact about pollen spreading through the whole house. I grow in my back bathroom. It is a normal small half/bath type of setup. While I was growing three nice Alaska Ice plants last year, I had a male WW and female WW under the bathroom cabinet, approximately one to two feet away from the main grow. I tried to keep in isolated by covering the outside of the cabinet with a sheet. Once every day, I would open the cabinet to water and check the progress. Man, you can really smell when the male is dropping pollen. Very strong earthy smell. Once or twice a week, for a couple of weeks, I would shake the heck out of the male just to make sure it spread. I got mass seeds, easily over 600, on what was in reality a really small cropped back WW female (it had to be small to fit under there.) The resulting seeds were excellent. Even being this close, my Alaska Ice only had maybe twenty seeds spread out far and in between on my three girls. So while it pays to be as careful as possible, it isn't like the pollen is a heat seeking missile either. BTW, the Alaska Ice/White Widow cross was shit. Nowhere near as good as the parent plants.
I plan on using the method described at the beginning of this thread for my next project. This time, everything can happen outside the main grow room. What I like is I can really experiment with different branches, maybe pollinating each plant with three different types of pollen. I don't need 600 seeds in one shot. If hit the jackpot, you can always get more seeds from the same batch later down the line.