i would set the angle at 1-2 degrees down, depending on how much spring wrap-up you have under hard acceleration.
then, you could fine tune it with wedges if it does things you don't like at speed or deceleration.
200 or 225 should easily burn the perches in. if you do this in small increments [1" at a time ?] jumping around after letting the first weld[s] cool, you shouldn't have any warpage problems.
if some are encountered, they are easily fixed, and there are several ways to do so.