Alright- so I've got myself an amazing old road bike that I've hardly stepped off since I handed over the cash at the garage sale. The guy had on it a brand new, giant cushy gel seat from Wally World that I might get beat up for if I try to call myself a "cyclist." So I'm watching ebay and all that, and I'm wondering- how does one figgur the right size of saddle, without buying 15 and throwing out the ones I don't like, or bending over at the bike shop and having a salesperson put a cold tape-measure to my sitter? Any help on this?