Glad to see this topic. I've recently done my first ever free motion quilting, using my 15K treadle. The feed dogs don't drop, so I set the stitch length to zero, then there is no need to cover them. I use a hopping foot. I'm very impressed with Vintagemotif's technical info on needles and thread. I'm far more slapdash. If the needle isn't blunt, I use it. If it's blunt, I chuck it in the tin with all the others. Then when I get a needle out I haven't a clue whether it's blunt or sharp so I have to jab one into my fingertip to find out. The louder the yelp the sharper the needle.
I have some pics of a doll quilt I have done with FMQ but I can't show you yet because it is in the post to my partner.....