Go to Ultimate's website- there is a chart that shows which model seat is suitable for smaller or larger riders. FWIW, I'm 5'10" and north of 210#, and love my Lowrider as shown. If you are bigger than that, you won't be happy unless you get the Big Boy model.
2003 1800C Black w/ H-K 3", PC III, Clearview w/s, Hondaline backrest, XM sat. radio, MB 12" shocks, Prog. fr. spgs., Wolo, SPyKER mod, Glen's gas cap, Paladins, Drag Specialties Popsicle pegs, K-N, blackened engine, Kury RTB, mirrors & r. boards, blue LED's, Rivco tach & risers, LeatherLyke bags, backrest bag, w/s tri-pouch, Gen. Altimax RT43, Mich. Cmdr. II, Ult. Lowrider, Showchrome grips. 12-18 VTXCafe Bike of the Month