Best way to increase Vacuum?

Disk brakes take more pressure than drum brakes to get the same level of stopping power. You can only compensate so much with the master cylinder bore because of the need to move more fluid with disks. Power disks will reduce leg effort and give you finer control over the brakes. IMHO, don't remove the booster.

To the OP; You need to measure the manifold vacuum you are getting, if you have 12 or more "Hg then you have plenty to run the booster and your issues is else where. The initial timing is a good place to look for more vacuum. If you have changed the cam it is very likely you need more initial timing than the factory setting. Adjust the initial to obtain max vacuum and don't be surprised if you wind up in the 15 BTDC range. If you wind up that high then you will need to limit the total by reducing the slots in the advance mechanism.