40 cm???? OMG; no wonder it didn't fit.

Ride the Cannondale and try to extrapolate from there. If you feel scrunched, then the Litespeed might work. If you feel stretched out on the Cannondale or just about right, then the Litespeed's TT is likely too long for you.

And don't let the shops force you into deciding between just these two bikes. Pour over enough specs, and you'll get some feel for whether other manufacturers will work for you. I cast a very wide net before deciding on my Bianchi. As for certain selling points of WSD bikes, like narrower handlebars, talk to the shop about making swaps if necessary to make a unisex bike work.