This is true when you're comparing torque and tire size. Toy fronts have stronger upgradeable moving parts (although I think the ring and pinions would be comparable, Toy is smaller but has a pilot bearing on the pinion). The upgraded Toy shafts will handle pretty similar torque to a stock 60 shaft.
However, the Toy axle has much less inertia than the Dana 44, so it will have a lot higher bending stress in the tubes. The knuckle balls on Toys are notoriously weak, and there's no way they would hold up better than a Dana 44 inner C, especially when you consider how much shorter the axle tubes are on the Toy (less bending stress). I realize there are ball knuckle upgrades, but in my opinion it's a custom axle at that point. You could build any center section with any outers you want in theory, and I don't really consider it a 9"/Toy/14 bolt anymore when it's only the carrier with custom outers. The Toy knuckles are also a lot smaller than the 44s, which means they're going to have a lot higher stress in the material when they're loaded.
If you were to put a built Toy axle and a stock 44 under the same heavy truck, the Toy axle would probably break less shafts from torque, but I'd bet the Toy housing would bend easier. Which means that Toys are going to get away with ~40s on a built stock housing, but only because the truck is light and the housing itself (not talking about the internals) doesn't have that much stress put on it.
I've wheeled lots of fullsizes on D44s with 35-37s without too much trouble. Leaving the carrier open will make a huge difference. You need to be proactive about maintenance like bearings, balljoints, and ujoints, but if you wheel with a brain and avoid bouncing tires and such, it will be fine. And as stated above, there's no such thing as a "HD" 44. The internals are the same. There are older external hub 44s, but they were all internal hub by somewhere in the mid 70s I believe.
