Carter TQ - VERY rich at WOT...how to troubleshoot?

OK, a brief update as I got a chance to try out a few things last night:

1) AV dashpot
- disconnected it, basically to rule out some kind of a mechanical obstruction that might perhaps impact the ability of the AV to open completely

RESULT => no change, there was a bit of a stumble actually, which I expected, but the AFR remained RICH

2) BOWL VENT
- disconnected the bowl vent in order to rule out some kind of pressure build-up in the carb bowl that causes the fuel to be 'force fed' into the discharge nozzles/passages

RESULT => no change, the AFR remained RICH

Given the above I think I will pull the carb next, disassemble and go back to the factory needle & seat assemblies just to rule out the float level being an issue. This of course will be reinforced by having the floats set to the correct 29/32 level.