Ranger Point Precision, Volquartzen, Tandemkross and a few other firearm companies are now using 'EasyExport' to export their products out of the US. So that's an option if Wolverine doesn't have the RPP stuff your looking for in stock.
I have a RPP Medium Loop that I switch around on my 1894's. AFAIK RPP doesn't sell replacement lever plunger/spring/pin kits. To use the RPP lever, you will have to change the lever plunger, spring & pin over to your new lever. I cut the flutes off a 3/64 drill bit to use as a punch. I put lever in a plastic bag and punched thru the bag to keep plunger & spring in the same room.
I recently discovered, Bear Tooth Mercantile. They have a another style of big loop lever & they have replacement lever plunger/spring/pin kits & they ship to Canada, I have one of their lever plunger/spring/pin kits 'in the mail'.