OP I think your services may have potential. I would recommend getting “in” with a few of the bigger A barns and offering a group rate. If you are able to get 5-6 of the bigger barns that stable at Palgrave, Angelstone etc. it would likely be worth your while. However, you will have to make it “reasonable” for them. Once you build your business/services then more may hire you.
Most of the Ontario A shows are based out of a few facilities and generally hourly checks aren’t done as there are always people up braiding, drinking (lol). Someone will usually come to your trailer if something isn’t right with your horse. Or, being a friendly Canuck, one will often help a horse in need (ie. stuck in a haynet) without hesitation.
Night check generally would consists of water, hay, blanketing and potentially handwalk/stall pick.
Good luck, and I’ll hire you next year haha…but I only have two showing.