The mounts for my rotary table, a Soba 6" are fine when the table top is horizontal, but I was not happy with it when the axis was horizontal. Some time ago, I added a small angle block to the side opposite to the mounts which gives better security. The holes in the base are for 8mm bolts, and blind, I checked the thickness of the casting while the RT was dismantled for cleaning.

The third photo is to better emphasize the narrow base and the offset fixture holes. The view from the opposite side from the winding handle is better, the RT is just balanced on the mill bed. There are no welds. The angle bracket was spare and good enough for the job, the 8mm screws are tightened into tapped holes with about 2 diameters of thread, there is no slop at all.

Am I right in assuming your RT was not intended to sit that way round, or are you also concerned with adding extra security?

If you ever needed to hold heavier work, you could easily use a much larger angle plate with screws at the top of the table base as well as at the bottom.