there is no real way to know how much your spouts will "twist" except for making a bunch and review the results. at a minimum knowing that the spouts DO twist will help you adjust things in the leather stage.
for me the twist is about 2° or so. small, but noticeable so i do the spout lip cut at around -2° to try to compensate.
notice too that mugs, pitchers twist and handles should be attached with this in mind. many times i look at a mug and think "i SWEAR i put that handle on straight!". it's the clay spring back happening in the fire...
see ya
steve
see ya
steve
steve graber