I've had the same problem in sunlight - there's a thread all about it somewhere on this board.
My solution was to really fill the applicator up, i.e. when you dip it in the bucket, don't remove too much excess.
I have found that if the squeegee "squeeks" on the glass then there's not enough solution on.
It doesn't seem to matter how much you use - if you squeegee carefully you can still avoid scrim work.