Why don't you get a window cleaner in, then you can see what he does.
The book is cheap for the bounty of knowledge it gives, for someone who is in the position of buying a wfp, I think its a small price to lay out.
Get as much water off with your squeegee as possible, then go round with your scrim.
I don't boil the scrims at all, just wear them in & throw them in with your normal wash as usual. All this talk about boiling, no conditioner, don't dry on heat etc. I can't see any difference. That hessian feel will go after a couple uses, & washes.