If the toilet flange has slots, you might get enough rotation by just sliding the bolts in their slots. If you're using the two fixed slots (generally stronger), that wouldn't work. You'd have to look at the construction of the adapter to see if it is reinforced well enough to put some new holes in it. There's not much stress on that connection if you follow normal practice and use some caulk to seal around the base after setting the toilet, so it would probably work. The wax won't care, it should seal regardless. The screws through the adapter into the floor are the primary means of anchoring of the toilet...the flange end only has to seal.