My experience with free turbines on helicopters and starting with the rotor held by the aircraft fitted brake or rotor held by an engineer until he no longer could there was no difference in start parameters, in particular EGT.
Should have been clearer that was in regard to the SAAB, it doesn't take much to stress it out on start, especially the A model engines. Might be that the CT-7 5A/9B have four stage turbines, 2 for each spool, might take more to push past the two aft stages when stationary, could be the engine was just not designed to have stationary Np. The prop brake was an afterthought and not very good from my understanding, heavy, and let go often with a few restrictions on it's use. Tailwind will bother the SAAB, but with the correct procedure you can start without too much difficulty. It is the same core as the T-700 essentially which powers Blackhawks, Apache and other helis, but obvious differences for adaptation to turbo-prop.