Falcon, my clutch master is frame mounted under the floor, and the slave is very nearly dead level with the bore of the MC. That puts the top of reservoir only about an inch above the top of the slave bore - that clutch master only has a nominal 1" ID x 2" high capacity. It's working just fine. Seems to me even with the slave slightly above you'd have to have a leak in the slave to let air in for the fluid to back flow to the MC? With a remote reservoir you'll be fine, I'd say.