GThose carbs are not veery good which is probably why it was removed from the cruiser. They are cheap enough,so if you get it hooked up ( not easy because they use a cable linkage) get it running then buy a new one from the local toyo agent.
Because it's progressive ,it won't use any more fuel unless you give the gas all the time.
You don't need an expensive adaptor plate ewither. The solex sits on a plate for the manifold heat,you can drill holes in that and use it for your toyo carb or..you can make one from plywood!. Yes it works!! I have seen it done often to insulate carbs from engine heat to get rid of vapour lock issues. Just use a piece of 3/4" marine ply or construction ply and you are in business.