I actually enjoyed learning to double clutch in my '47 Merc/M-H, but I can also just "single" clutch and let the revs die down if I'm not in a hurry. Super-heavy gear oil helps too.
Are you sure it's a Mercury speedometer? I think they came with a trip odometer in '46. I just noticed it's a Canadian Merc 114, so maybe it's a Ford speedo.
Originally, one is the high beam indicator; the other is the turn signal blinker. There should be a small rectangular cut-out plate on the left side of the cup at the top of the steering column, which was for the now very rare factory turn signal switch. The ones in my '47 are now L and R turn...
I suggest you join the National Woodie Club (link below). We have a comprehensive website and publish an excellent monthly magazine; advertising (BUY or SELL) is free on both, and you'll get a good idea of current values. From what I see in your post, woodiewagon46 has the best practical advice...