Honda-SOHC

Yes, red and white wires are o new coil and yes they are supplied overly long.

Thanks for the tip!

The correct fitment LED replacement from Classic Car Leds seems the sensible option to me Ted, it'll save the charging system a bit and suit my other led upgrades.  It's 3mm longer but I don't think that will cause a problem in the original headlight bowl.

Usually the lens will have 'H4' in the center of the glass, if the reflector is fit for halogen bulbs.
The socalled 'charging shortcoming' of the these bikes is an urban myth. I've had a 55/60 Watts bulb all those years - my model came standard with it! - and never had a problem, not even with 3 Ohms coils and a transistor ignition. Every ride I return to the garage with a better charged battery than I took of with. 44 years of experience here. I recommend Philips. The Extreme Vision Moto H4 and Osram Nightbreaker came out best in tests and that Philips was especially developed for motorcycles and can cope with vibrations up to 10G.

Sorry I slightly misunderstood your question.
As has been said the current draw of a modern H4 Quartz Iodine bulb might be a tad high, the other consideration is the dip pattern cut off  might not be good.

I am a fan of fitting an LED bulb as I did originally on my 400. Beware of cheap ones off eBay I had one that stopped working after just a few on & off cycles.
I sent a message to LED classics to find the right bulb as the important heat sink can cause issues of being too long when fitted either inside the light unit or outside. Again as the reflectors were designed for the build design Honda used there will always be a compromise in terms of scatter and dip cut off.
If you search the posts Oddjob did a lot of research on this with photos of the result of using different bulbs. I suspect like moths are attracted to light we are attracted to big Lumen numbers. In the end that's why I fitted a  complete headlight designed from the off for LED only use so the reflector gives a good dip cut off and a nice high beam plus low current draw.

Are the red and white wires shown the ones on your new coil as they look very long?
If they are then look at polarity markings on the coils themselves they should be marked +ve & -ve.
As the points earth the LT side of the circuit you need to ensure that the polarity matches.
So the negative side goes to yellow or blue for the respective coils. I would consider making up wires of the correct colour.