Yes, I understand what a locked distributor is, but maybe I should restate the question: Have you had a timing light on the motor to see what the actual timing really is ?

You said: "...Static timing has been set at 20, or 30 deg. It's a very hard motor to start...". Well, is it 20 deg. or 30 deg. ? Are you sure that your TDC mark is correct ? I've seen VW flywheels put on all sorts of crazy ways, and the motor will start and run, but the timing marks are whacked and the motor acts bizarre.

I haven't seen a ABA 2litre crossflow motor, but if it's anything like all the other VW motors I've seen, while the distributor can be locked down, you still have the option of getting the timing all screwed up. Does the distributor hang off the end of a cam (a la Cosworth), or is it off the jackshaft ? Is the locking collar tight ?

Please tell me that you own a timing light. Please please please please....

Until you know for sure where it's firing relative to pistons and cams, you're just re-arranging the deck chairs on the Titanic.