Typically the flange should be screwed to the sub floor. Then tile around the flange. It works best if the flange is flush with the finish floor. When this is the case a normal sized wax ring (medium) with a horn should work perfectly. When you set the toilet, if you do not feel it squish down at least a half an inch, pull the toilet and go with a jumbo ring with horn. Then test it several times before caulking it to the floor to ensure no leaks.
Note: Do not rely on the caulking to hold the toilet to the floor, that is the flange bolts job.