OEM oil cooler install (non tow package)

Question about the stock 1GR-FE tow-package oil cooler, as-installed (as it comes from the factory) --

The stock oil cooler gives "X" amount of active oil cooling capacity, above and beyond the passive cooling offered by engine-block and oil-pan cooling via radiation & the general coolant system itself.

Is there considerably more (i.e. X + 50% or more) oil cooling capacity to be had in other, larger after-market oil coolers? If so, any specific parts or manufacturers people would recommend for this?

The use-case here would be for towing heavy & uphill, i.e. where it might be necessary to push 4K+rpms under load for many minutes at time, at 35-45 mph. (6spd MT probably in 4th gear.)