You can use the original Gibson screws with Schallers if you don't mind about 15 minutes of work. I've done this on a couple LPs and it works great.
First, the strap button at the bottom (bridge) end of the guitar is larger than the other one up by the horn. The reason for this is that during the manufacturing process, the bodies are hung upside down by the bottom, so they need a hefty screw for that.
To use the original screws with Schallers, do this:
-On the screw by the horn, you need need to drill out the hole on the Schaller and make it a little bigger. Use a drill bit slightly larger than the hole, and do this one or two sizes bigger until the Schaller fits through it. Then install the button.
-On the screw by the bridge, put the big screw in your drill, threads first, so that the screw head is sticking out. Now run the drill, and press the rotating head on a file. This will slowly reduce the size of the head. You will also need to make the Schaller hole bigger, just as on the first screw. When done, you can install the bottom button using the big screw.
When done, you'll have two tight fitting buttons, no toothpicks or glue needed. And the other thing is you can always revert back to the stock buttons, the modified screw will still work with it.
Hope this helps!