I think something that is overlooked when starting spins is suckin up the lower body. It is easy to get stuck in the 'I need the perfect rotation' mindset. Part of a floaty spin is air time. On smaller features you can significantly increase air time by bringing the knees up.
For spins on groomers and small rollers I tend to Ollie backsides and Nollie fronts to get a more floaty look. I do tend to put more rotation into them as well. Less height means faster spin.