Hi

Not entirely sure I've understood your objective, but...

The Ottoman's/Seljuk's main threats are the Byzantines and Fatamids (Egypt). So, if you want to assist the Turks you need to stick it hard to one of those two. From distant memory, the Byzzies pose the more immediate threat, so engaging them (maybe as the Hungarians) might get their attention and divert resources away from the Turks.

I also seem to recall that the Eggies ruler is very exposed in somewhere like Tripoli, which gives the Turks a chance of a huge ransom if they blitz and capture him.

Hope that helps.

Regards
Victor