Re: BUT I LOVE duck tape!
for the woman's bike, you can purchase a bar that attaches between the seat tube and the top tube or the handle bar stem that turns it into a men's bike for mounting purposes. Or, you just kind of wedge it in however it will stay. usually one bar under the seat and the other under the frame. it tilts the bike at an awkward angle but it works. you have to do the same thing for the kid's bike. they're too small to span the gap of the mounting bars so you just kind of have to get it on the rack however it fits.