Welcome to the forum, Smoke.
When I first became aware of the SVD-185, I thought the combination of it and the TTS-100 setting tool was the most advanced combination in the Tormek lineup. Although it is still a tool tool, it is in second place when compared with the SVD-186. Of all the Tormek lineup which I have used and reviewed, the SVD-186 has been the only tool I have given an unqualified buy recommendation to, even for users happily using the older design.
You could solve your fall off problem by cutting off some of your SVD-185 tube. I have both jigs. If you choose to do this, I will gladly measure both for you and post the cutoff measurement. However, this would be short sighted. The shorter tube for T3/4 users is only one of the redesigned features. The hex key screw of my 185 is somewhat stripped out. The jig setting can slip. The 186 uses a positive ratchet stop set up with a locking knob. This is my favorite improvement. The 186 is made of zinc. It is heavier and has a satisfying feeling of solid heft. Going by memory (I'm away from my shop.) I recall that the clamp was also redesigned. It works better with small gouges and, I think, will also handle larger gouges.
In case I have been unclear, I recommend the SVD-186.

Ken