I tried your settings and I think you got it dialed in pretty good in order to get it to behave similarly to a slow moving DJI style drone.
As you say, of course you will still have the spring loaded throttle issue, but I think it will be good enough for practice anyway.
If you stick with it, I think that soon you will get the hang of it and you will be able to keep it at a pretty stable altitude without much effort.
(I don't think setting the gravity to 0 would be very beneficial, since you wouldn't be able to get down at all)