i can only speak for the pt6a-41 on the cheyenne III i ride but i must say start malfunctions on start are rare.
one start get hotter than the other , but generally- keep cool. spin the core until no further increase in ng is possible, kick in and look. the ITT may shoot up, the compressor increase slow, but it mostly stabilises.
when the engine does not reach itt limits i do not abort and it mostly start to run.
a hung start is very rare, but may happen. also here, do not abort to quick, look what the engine does.
i had also a wet start due to a faulty ignitor box- ok, here you can stop and call for a mechanican.
at 1000 deg i keep on going- limit is 1090 :-)