for assist macros, do you mean to let the group know you're assisting them?
So far as casting master abilities with a macro goes, I can tell you what to do there. It's helpful to go ahead and combine multiple master abilities in one line bc sometimes with a mob you aren't sure which one will work against it due to resistance. Here's a pattern you can plug and chug with:
/:;usea orc masters strike; usea skeleton masters strike; usea elemental masters strike
You can edit this to suit your particular spell line. By separating the separate spells with ;'s it will be sure to be effective cuz one of em will work against the mob LOL
anyway, it's by using the /: followed by ; to separate the multiple spells, the command word USEA followed by the name of the spell.
Hope this helps out somehow ;)