You are correct, an AT 235 is a 40'-42' working height and the SU34 is a 34' working height bucket. the problem with the SU buckets are finding anyone to work on them or to find parts. Ever since Altec bought out Telsta the parts have gone way up and availability on them is crap!!
This is CABL.com posting #373672. Tiny Link: cabl.co/mbJm8