I cannot provide numbers, but a few I recall, which may be taken as typical of the 1972-82 period, on the Nenagh branch, and Rosslare - Waterford - Limerick, Limerick - Athenry - Claremorris - Ballina, and Mallow - Tralee.
I travelled behind 190 or 191 one sunny evening from Rosslare to Waterford. It has a Dutch van and three laminates. The service from Rosslare to Limerick often, in those days, had 4 or 5 bogies, but with enough passengers to put in one. I never saw a Craven once on that service at all, though of course the odd one might have put in an appearance. The service was almost always 141 / 181.
The Limerick - Ballina was usually two carriages and a van. The van was a four wheel genny - in fact I think this was the last line they were used on. Latterly it was a BR or Dutch. No Cravens - here it was the last few Bredins, Park Royals and various laminates (usually laminates). Haulage was within that time almost exclusively 141 / 181 type.
Mallow - Tralee could be an "A" or a single 141 or 181. I think they sometimes used an engine that had been on a goods - which would explain an "A". Bogie vans were here earlier, with up to five behind them. As well as the inevitable laminates and Park Royals, which formed most rural services (plus Cobh), this particular run might also include Cravens.
In this period, main line services on all lines were indiscriminate mixes of Cravens, Park Royals (including former suburban types), the last few Bredins (up to about 1975/6), and all the variations of the laminate theme. 24XX dining cars were the norm everywhere, Cork and "Enterprise" included, irrespective of what stock was used - with the exception of the Mk 2s, the forst air conditioned carriages.
From 1972, these AC stock were introduced as the "Supertrains", quickly taking over many main routes. These ran in sets, never being mixed with other services, except if a mail train of Mk 2 had an older TPO or other stock behind it, or in the case of an AC train taking locked-off stock trailed behind it. Even this was exceptionally rare, and it may be taken by modellers wishing to run accurate trains that for any period when both AC and non-AC stock was running, that the rule is -
Supertrain - BREL Mk 2 stock ONLY, with appropriate genny vans. Not Dutch or BR vans, let along 4-wheel ones.
Everything else - anything BUT Supertrain stock, mixed and matched.
So - that means (in the BnT era), any four wheel van, BR van or Dutch van, can run with any Craven, laminate, Park Royal or Bredin. Up to 1974 in the Cork and Dublin area, an occasional (now BnT) old GSWR wooden bogie too. Sets all of one type would have been very rare indeed, even on the Cork line, where the dining car at least would be a wooden-framed 24XX type, as at Downpatrick.