Xi I don' t know the exact Ke for your setup but I would think you would have to be on the border for using most mechanical heads and the Miniblaster would not be one I would recomend. If your thunderheads are shooting well for you I don' t see a reason to switch.
I think rocket has improved their heads over the last few years. They still are not the most durable on the market, but seem to have got better over time. While this is not my first choice in a mechanical, I would feel comfortable using it on deer size game with my setup.