why not use the PT drum grid editor? if you have the bars aligned correctly and a tempo map that deals with the variations then the drum grid editor can play a midi hihat exactly as you like and fill in as many bars as you like. you can even change the pattern for different sections.

it would be on a different track and can then be balanced with the mixer.

and in a mix a midi hi hat should be indistinguishable from the real thing if you have a decent soft synth (actually even a bog standard synth should be ok)