A pre-washer and starcher here as well. In addition to removing the sizing; checking for bleeding; etc. with pre-washing it also gives me the opportunity to iron and refold the fabric more closely on grain vs how it may be on the bolt.
I use liquid starch mixed at a 50/50 ratio w/water. I prefer the sta-flo brand. Mix up small amounts at a time as I need them. Starch is particularly helpful when dealing with bias edges.