Cant advance timing enough

[Jack91]

Hi all, played with timing on 351c in the bronco today, was pretty retarded, I assume due to lpg (only on petrol at the moment). Couldnt see my timing light due to the sun so did it by ear, I turned the dist clockwise until the vaccuum advance diaphragm hit the thermostat housing. Heaps better but needs just a smidgen more. Am I able to move all the leads around one space, then go back to give myself more room? If so, would they all have to move one space clockwise or anti clockwise? Started to confuse myself so thought better ask first.