1-2 inch pin. A tropical will get through the most burnt heads on its own and you want smooth rolling. I would go with a 1-2 becasue for that reaction coupled with how easy the Tropical is through the heads anyway, a pin below drill should be your choice. Pin above is going to be stronger on the backend. Yes, a Tropical has the ability to come around hard in the backend on some conditions.
TW, I personally have not notced much difference with them so, whatever they send you should work.
