shaky 1st gear, hard to start,

[John Z]

Not to be a wise guy, but how familure are you with driving a clutch. Assuming the mechanicals are well, your problem might be with the left foot - right foot coordination. I only mention this because my spouse has trouble with my mustang and I don't.
Another thing to check is the clutch linkage. If you have a stock linkage, you want to make sure everything is aligned and not rubbing on anything and the pivot points have minimum friction, especially the bearing between the clutch pedal and the pedal support.

The easiest way to check for vac. leaks is by spraying some combustible fluid, like WD 40 or starting fluid, around the engine where there is potential for vac leak, like the base of the carb, around the intake manifold while the engine is running. If there is a vac leak, the fluid will be sucked in enriching the air/fuel ratio and the engine will speed up.