this is a very interesting topic for me as, some years ago, i had an inner ear problem which caused me the sort of dizziness associated with spins and turns. I had to learn to overcome this in my everyday life, and perhaps i can pass on one or two tips to help with the dancing.
I found that taking a sea-sick tablet considerably minimised the effects of the dizziness - in a way neutralising it. It might be worth taking one about an hour before you start dancing. It could make you slightly drowsy of course.
Also, i used to practice viennese waltzing on my own round and round the room, doing repetitive naturals, or repetitive reverse turns for about 3 minutes, then after a minute's break, doing it again..and again... This 'forced' my brain to acclimatize and after some months of this, i found the effects of turns and spins to be negligible. It's also a brilliant zero-impact aerobic exercise!!

These things worked for me - they may not work for others. The ear problem is gone (i hope!!)but i can spin and turn as much as i like without any dizziness.