Will I have to remove the upper half of the intake manifold to get the rocker covers off?

The passenger side looks like it will be right, but not too sure about the drivers side.

If so are there any decent aftermarket gaskets or should I just stick with a genuine ford one if theyre still available? I've got Felpro gaskets for the rocker covers but didnt notice whether they make one for the intake.

Just use the Felpro gaskets.

Popping the top off the manifold isn't too bad. Just four bolts I think it was, then pull the vac lines off... If I remember right that is!

The factory fitted Ford steel/O-ring gaskets are the best. So good in fact that I save and re-use them. Haven't had a leaker yet