Brushing Putty Into Lead Cames

Hi All,

I've always used the edge of my thumb to push putty under the leaves of the lead came. I'm on a big project right now - a 12-piece, 27 foot entry - and I thought I'd try the brush-in method this morning. The result was less than thrilling. Took as long as doing it by hand, didn't fill as well, and left a bunch of putty in the brush. I thinned the putty (I'm using AmChem) down to brownie mix consistency with a half and half mix of linseed oil and paint thinner. What did I do wrong? Any tips on how I could have done better? Or should I just keep on doing it manually?

thanx-

~s