Welcom, 7.62man. Like Stimpy says, I've never heard of a pivot base that would fit a Handi. And it shouldn't be too hard for a smith to make a couple of extra holes in one if you can find one that fits the radius of the Hand barrel (if not, see a couple of sentences below).
As for the aperture sights, if you have a barrel with factory sights you should be able to use just the WGRS rear sight mounted in the holes for the scope mount. Sound a bit excessive to pay $120 (even in Canadian dollars) for the whole set. I have used the WGRS rear sight with the factory front sight on a 357 mag, a 357 max, and a 30/30. Even modified a rear aperture from something else and screwed it on one for awhile. (put a piece of emery cloth rough side up on the rear of the barrel and sanded the heck out of it to get the right profile/radius for the Handi barrel).
Where in Canada are you eh? I lived in Kamloops and Vancouver Island for awhile - also near Peterborough ON.
Cheers
Kerry