Vintage Christmas lights

I'd welcome advice from the forum on this. I have an old set of Christmas lights from my mams house, at least 60 years old. They were originally a 12 string set with 20 v bulbs (3 watt I think) They are wired from lamp holder to lamp holder with a return wire. If I remember correctly both wires were attached to a plug and away we ran! I'd like to reinstate them if possible as they are of huge sentimental value. 9 of the original bulbs still work. I've read on other forums that its a good idea to utilise a dimmer switch to avoid a sudden burst of current - is this a good idea? I've also read I can add additional bulbs to the string to reduce voltage. Again is this correct? I'm reasonably handy but wary of doing the wrong thing and either blowing the original bulbs or sending the house up in smoke. Advice welcome!

If you get a 110 volt transformer ( the type used to power a 110 volt power tool) you will then be able to use 6 of the working bulbs as a string. What is crucial is to have the correct voltage across each bulb. 6 bulbs across 110 volts will be perfect. You could also use a string of all 9 bulbs off the 110 volt supply. They will glow slightly dimmer but will last for much longer.

I'm not an expert on electricity and I worked as a sparky's mate many years ago. My initial reaction is that the wiring of the lights from the 1960's could be suspect along with the lights' connections. The old wire might not be as pliable (and may easily break) unlike modern wire. Therefore, I'd dump them (but that is just me).

Just saying:- It might be the light attachments (imitation lanterns, coaches, etc) that are important to your memories. If this is the case, it is easy to take them off and attach them on newer lights.

I gather that the lights are important to you and you have been given safe and good advice by Bstop. Hasten slowly and carefully if you are continuing to use the lights.

Don't put the bulbs into newer fairy lights. They probably won't fit but even if they do it won't work safely. You must have all bulbs with exactly the same resistance. If there are different bulbs with different resistances the voltage drop across each bulb will vary greatly. Some of the bulbs will burn out. They might even explode.
Yes check all bulb connections and the condition of the wiring insulation.
With the transformer you will be operating at 110 volts center taped to earth so the voltage to earth will be only 55 volts. With good bulb connections this set up will be much safer than the original set up.

Is there a transformer in the plug or a little box along the power lead or is it a simply run of cable from a standard plug to the bulbs? What kind of bulbs are they? Do they use a standard holder type? Most of the older lights will use some form of common holder, in those days you didn't throw the whole thing away because a bulb or two failed.

If we can't source replacement bulbs, are we just talking about a simple string of bulb holders or is there some form of glass or plastic decorative cover? If the latter I'd suggest canibalising a set of LED christmas lights to wire individual lights into the holders or have someone competent wire in and attach a suitable driver.

Sounds like a project for https://www.bbc.co.uk/programmes/b08l581p

Anything of any use here?