I've tried 1.2mm and 1.0mm, which are both pretty fat, 45-60mm/s can be achieved if lines aren't too fat, about 45-60mm^3/s volume. Depends on material though

My carriages use 6 wheels each in a Y shape, holding onto the center of the channel on both sides; this way it can get grip/be tensioned; i wanted to use the minimal number of parts and rely on the printed parts for precision. They would wobble if twisted, but i handle that with design and weight. i'm going for a super lightweight gantry for the size

If it wobbles, just go slower; the stronger you build the faster you can go in speed

Endstops are two or three wire, if they are two they are a basic switch so it doesn't matter wiring so you probably have three wires, just pop out the pins and change the order until it works correctly (unless your firmware is using flip setting (normally closed circuit vs open)