Why waste your time removing the manifold.  If you leave it connected
to the exhaust system you can most likely just unbolt it, move it an
inch or two away from the head, remove the old gasket, slip the new
one in (spray it with copper gasket stuff if you want to increase the
odds of no leak, I think I used permatex), and bolt the manifold back
on to the head.  I've done this on two different vehicles over the
years.  On one of them that had headers I didn't even replace the
whole gasket, just teh section that was leaking.   If it doesn't work
you can always do it the hard way later.