In its day, the Topolino was the short boat with rounded ends that was the first choice for steep creeks with a high pinning risk and used for some truly gnarly first descents.
The Topo Duo is the classic two-cockpit whitewater boat based on the Topo, with rounded ends not only to reduce pinning risk, but to keep it sensibly short and cockpits still far enough apart for paddlers to be able to make different strokes. It was produced for something like twenty years and was only recently discontinued. Second-hand ones are rapidly snapped up.
It's ideally suited for a more experienced paddler in the aft cockpit, to take someone less experienced on a river that they wouldn't tackle in a boat on their own and as such it's an almost ideal boat for a club. But with two paddlers who know what they are doing, it's capable of some epic descents. Be aware, though, that the front cockpit gives a wetter ride in waves and the front paddler may be submerged for some time when going over drops like Low Force or Richmond Falls.
Topo on Low Force - yes, they stayed upright.
If your less experienced paddler is also not doing that much of the paddling and doesn't own such good paddling clothes as you, cold can set in quite rapidly. It may be harder than you expect to avoid the splashy waves, as the view forward tends to be blocked by the front paddler. On the other hand, putting the more experienced paddler in the front seat produces much less paddling power and control (particularly if your "expert" is heavier than your "beginner") than the other way round, and is not really recommended.
Topo on the Wear - Durham to Finchale Boxing day trip
A quick health warning: if you are taking it creeking as two experienced paddlers, make sure you both roll on the same side - if your preferred rolls are on opposite sides, agree which side you will try first before you put on!
Statistics: Overall length 3.71m, beam 63.5 cm, paddler weight range: pretty much anyone who will fit ! from two kids to two adults.