Yes, TH I'm going with the clock block from Moss.
I had the wife hold the side view mirrors at various locations last night. First I had her hold the side view mirror over the mid-line of the front wheels. In this position, the right side view is blocked by the rear view mirror, so that is no good.
I agree with someone above who said the door mounted position requires too much head turning. Maybe it is my short legs, but I sit too far forward in the cabin to see side mirrors on the doors of the Healey.
I then tried the position over the front tip of the fender spears, but they would just be in the way when working under the hood.
I then had the wife hold them over the rear point of the fender spears. This position gives a good field of vision. The mirrors line up with both the rear of the spears and the rear hood line. Plus, the mirrors are now out of the way when you are working under the hood. Installation at this point is going to be a bit difficult. On the driver's side, I can just reach the underside of the fender above the rear of the spear. I will have to think through the assembly, because if I drop the washers and nut, I'll have to remove the bolts at the bottom of the fender to get them out. On the passenger side, access to the underside of the fender is blocked by the paper tube running to the heater. That will have to be removed first.