Basically the engine should be able to maintain a good idle with only 5*BTDC initial timing.
You say you disconnected the vac advance and it lowered the idle too much but you still had 8* initial BTDC, which is enough to maintain a good idle given the motors not a pos worn out 8 hole flower pot.
So if the idle was too low at 8* then you need to raise the idle at the throttle lever with the idle mixture screws out 2 turns a piece and remember how ever many turns they are out they need to be the same amount.
