I welded the bolt on in a dodgy attempt to get more metal for the disc to sit on and bolt too. This was 10 years or more ago and this is why I'm having hubs machined up now to do it properly. And also to remove the need for cutting the original drum up for a spacer.
The wheel won't hold the disc on because it bolts in from the back..........not over the hub. No car uses 2 bolts to hold the disc on that I have ever seen........minimum 4. 2 would be just plain dangerous. Some may have locating grub screws if the wheel holds the disc on but not for a disc on the back deal.

I'm not saying this conversion is the bees knees......its just one of many options out there for the 1000.