If you haven't got it yet, If you're talking about the clutch to the motor, I would just put whatever socket fits the tightest and go from there. Could be sae or metric.
I know Landmaster does have a decent online support as far as engine, tranny, motor, etc, manuals. You might be able to find a diagram breakdown?
I know there have been a couple of HF retrofits on these forums and Youtube if you haven't looked at them yet, they may have some ideas on other things you might run into also.