Drilling the plug sounds bad. The center of a sparkplug is ceramic, and it'll just break all the way to the plug tip.
Is "PB" like penetrating oil?
You can also try freezing the plug with Dry Ice. It might make the hole expand while the plug shrinks. (Safety equipt like tongs, gloves, googles, etc. is mandatory, or you can get bad burns).
Anyways, on a 93, you can improve access to the plug by removing the exhaust manifold.
You could try cross-drilling the plug.