rollers should be 10' peak to peak if 12" high. Berms should begin and end with a roller, account for this in measuring. Rollers shrink by a third the first year, (account for this when building). if the rollers feel abrupt they are not "sine wave shaped" enough, (the tops should not be a peak, but a smooth curve).

I built the Northern-most pumptrack in WI 7 years ago.
:)