I used a small long bristle soft brush to get the stray grounds out from behind the screen. It is important to align screen to that the bottom edge of the grinder exit chute and the inner edge of screen line up.

I agree that it's counter-intuitive to mount he screen to the funnel. The first time i did a doserless mod I attached it to the grinder body (which the instructions I sent you still illustrate as the desired method.) Since then I spoke to my supplier about it and they suggested attaching it to the funnel. The gasket is so thing and soft that the shape being different than the areas it lines up with on the grinder body really makes no difference. I do see the benefit of being able to get at the chute by removing the funnel, but if you don't use oily beans it shouldn't ever be necessary to do anything other than brush out the stray grounds that sit behind the screen. Option B is you just run the grinder for a second or two at the beginning of the session and discard those first grounds that come out (which are the left overs.)

My pull to dose routine was so ingrained that it took me four or five days to get accustomed to doserless use - after that I referred it.

Or keep a small vacuum handy and suck old grinds out prior to new beans going in the grinder!

I'll try a few ideas and see what works.