OM table top macro: Lighting and exposure?

I have an OM1n, tripod, Olympus bellows inc. double cable release and a Varimagni finder.

What else do I need for table top macro? Will be used when minding my grandkids, currently 8 and 6 yo. We'll go for creating some kind of story book involving pics of their Hot Wheels cars and action hero figures etc.

I'm tempted to get an OM2n for the otf metering and guaranteed(?) correct exposure. Worth having just for macro?

For lighting, I see led ring lights that are only £20 or less brand new. For almost 3 times as much I can get a 30+ year old OM ring flash. Are the cheapo led rings fit for purpose or should I stay with Olympus kit?

If you're not that serious about it, the cheapo LED ring lights should be fine. If you ARE that serious about it, I'd go with something better than a ring light, and I probably wouldn't use a film camera for macro unless super shallow depth of field is what you're after. Digital kicks the snot out of film for macro due to it's ability to focus stack in software. And to be honest with you, I'd rather use a couple of soft boxes than a macro ring light. I've never found them good for much other than a catch light when shooting super close ups of people's eyes, or as a cheap, portable, and easy way to light bugs in the field. In a controlled studio environment, they're pretty useless, in my opinion.

If you are up for some serious OM film macro effort, I have a nice package of stuff that would further that end, if you are interested. https://www.fredmiranda.com/forum/topic/1576779/

The OM-2 and OM-4 OTF options are worth it if you have OTF compatible flash light sources. And the long exposure metering capabilities can be useful if you are working with low light levels and slower film.
Otherwise the OM-1n should be fine.
You didn't mention a lens. Something designed for use on the bellows would be nice.

I'd think that a bellows may get you too close but I've been wrong before. Close up lenses may make a better
option for both working distance and no need for compensation. Yet another choice would be a macro lens
the ability to go from 1:2 or 1:1 to infinity give a huge amount of flexibility.

Back to lighting though, a light tent would be easy. They're used by a lot of people to shoot items
for sale on the bay
Personally I like using a constant light rather than flash.

You might want to use a long lens (e.g.long zoom) with extension tubes or similar. Vivitar 70-200 is cheap as dirt and might be better (for this particular purpose) than anything from Oly.

Getting close to the subject may not give you what you're after. A macro zoom lens like that Vivitar might better meet your needs.

You might want to crop the light tightly (i.e. mini barn doors or toilet paper tube).

TTL flash exposure greatly simplifies things when you are capturing the object at greater magnification than about 1:4 ().25x) and the light striking the film plane is dimmer than a light meter indicates is 'proper exposure' for the shot.
Whether a ring flash is suitable or not is a different issue. A ring flash provides 'omnidirectional' shadless illumination which is often what is wanted by an scientific or indistrial photographer, but which seldom makes for an aesthetically pleasing shot that most hobbyists are striving to make. Better than a ring flash is a unit which flanks the object on two sides and which allows one source to be somewhat different in power output than the other light, so that some 'modelling' of the object being photographed takes place and makes for a more aesthetically pleasing shot.

An architectural model that needed to be photographed from "street level" was lit by a couple of flashlights.