Dominator ignition timing

Its most likely that you have a dynamo system , so you will need to mount a degree disc on the primary side crankshaft , clamping the disc with the sprocket nut and some big washers . I would use a mains powered strobe gun that will enhance the signal that you get off the ignition lead . A pointer fabricated from a wire or strip metal attached to the engine  and a  piston stop tool to set the disc and also to indicate the advanced position. The main issue is often trying to ensure the disc does not slip when you rev the motor. I guess you have an Ei conversion fitted to a mag or later points housing (mushroom)?.

You are going to have to use some form of piston indicator so that you can read when the piston is at TDC  ,usually you stop it an equal amount both sides of TDC  and set the disc in the middle of the readings  then   fix a pointer  to an engine bolt  ( I use a bent strip of metal)  and arrange it so that it points to 31 Degrees  BTDC (for a 99)  on the disc. With the engine running and strobe connected  the strobe should illuminate the disc  by the pointer when revved up to approx 5K . Timing is adjusted by rotating the ignition unit (dont know what you have!) . I have given up on this nonsence for years  and do it all by ear and feel !. You can make your own stop  by using a bolt or similar ,but be carefull. not to damage the piston or valves   (do it on the compression  /firing stroke)

Feked do a nice piston stop/tdc finder, but they are £20 :(

https://www.feked.com/positive-stop-timing-tool-10mm-12mm-14mm.html

I as well as Robert set my timing up by ear and feel and wouldn't trust using a factory degree setting with modern fuel.

With the Boyer, I set it statically as in the instructions and then go for a ride.  In top gear between 30 and 40mph, I open the throttle and listen for pinking.  If it pinks, I retard it a little and if it doesn't pink, I advance it until it does and then back it off (retard) a tad.

Being able to  easily adjust the timing  a small amount  is a major factor . With the mag  it was not easy as you have to remove the timing cover , break the taper of the advance unit ,etc.  I have a distributor ( like an old car )  so it can be moved , although I tend to make small adjustments by tweaking the points gap. This does not affect the dwell (on my bike) as I also have electronic assistance to the process and a built in timing light on the black box. I also have a guide  when  things are right in that  its just possible to provoke a tiny kickback when starting , and there is a lively feel to the motor and a snarl in the exhaust tone. 

As for wiring...the cables last pretty much forever unless physically damaged. End connections are the critical places that need to be sound. I have a 30's bike with most of its original wiring, and an 'earlier restoration' that was rewired in 1957. Unless you are looking to win concours prizes with a perfectly clean as-new (and possible non functional) machine, I'd do things that really make it better.

My 6v dynamo 99 has its original wiring. The painless way to refresh the wiring is to replace all the bullet connectors, as there is enough slack to clip off any oxidised ends as you go. The original cables are correct for colour coding, which makes following the book easy. If you get good LED bulbs (from Classic Dynamo Regulators or Ozzy Osborne) your 6v system will be perfectly good for night riding AND you can the headlight on in daylight to help save your life.. It's worth running an extra wire to earth the headlamp as LEDs consume so little power that good earthing is essential for reliability. Then you can also have a smaller sealed battery in the box. Think about putting an electronic voltage regulator/cut-out in the original 65 year old casing for peace of mind.

I bought a 6V 'Daylighter' bulb from Paul Goff. It's brighter than standard, but not dramatically so.  The beam is less well controlled. 

When I got the bulb, I tested the current consumption, and it's less than 1A. Standard tungsten headlamp bulb is 6A.  I would much rather have a MUCH brighter headlamp, say 3A or 4A, with a good beam control.