Have you tried a smaller slide that would fit on your pinky?

You would still have the first 3 fingers available for soloing and chording.

I only fart around with a slide and this is the way I use it. Started with the 3rd finger thing but had someone suggest the pinky thing, made sense so I have been doing it ever since.

Biggest problem I have is, eventhough I use my first finger to reduce the vibrations "behind" the slide I still don't like the tone I get.