Rotax 582 with engine mounted radiators as used on Thrusters and trikes etc have twin radiators. Flow is in series. Twins are used by Rotax in this situation because it makes a better package, reliable mounting etc.
There are two sizes of radiators used on 582, standard and tropical. The small sizes cools 65hp on very hot days at low airspeed, 35-40knots. The tropical may have enough area for a 100hp 912, they are supplied by Rotax.
We recently had a Sling tsi at the shop. The way the coolers were mounted was pretty neat. They just clip to the cowling, no air leaks, reduced vibration on the radiator.
To get maximum efficiency you will need cowl flaps. It is a simple way to reduce cooling drag when you don't need maximum cooling.