Answer to fabric under the needle question....Back when most of us took Home Ec, our machines were manual, which meant that had to oil them. The fabric absorbed any oil that gravity took down the shaft to the needle area. Now days, it helps cushion our foot and feed dogs while lugging our machines around. (didn't do that years ago too much, since our machines were very heavy)...unless you had a Singer. Funny how we never get out of some habits.
I always leave my foot down and needle down.
Diana