Your slide bait/Float idea is what I intend to try using dead bait

I suspect that the resistance that the float will incur will soon tire out your live bait as it attempts to get away from the surface and is pulled back up (Assuming that the float's buoyancy is sufficient to achieve this)
But most likely no more than the use of a balloon would.
The slide technique will keep the live bait in a smaller area than a balloon so I see why you pursue this. I remember those lovely offshore winds in the HB fondly.
You haven't mentioned it here but your technique implies you will not be using non return sliders.

Does this mean you use a coast lock or similar slide? I ask as I have made several models of slide clips including a couple of non-non return cages with and without weights as I see using the coast lock as a risk - Smaller surface area where the line is on a single point versus multiple points spread out when using a spiralled cage.

I know other posters here use coast lock's successfully and if the coast lock is sufficiently strong it isn't the point of failure but the line against the wire I am not so confident about.