I know Alumitech is using Moog front end bushings for mounting the gear box to the stand, they are rubber and I had to put steel bushngs down the center of them. At least that is what they told me to buy when I had my new engine stand built. Hope this helps.
I have the steel slugs that are tapered in and the have polymer cones that fit inside a stock gm motor mount and the rear they have a polymer cone on the top and rubber cone on the bottom . This is what hamant uses and I have found that there are about 50 differnt type / style of motor mounts these are simple will post pictures of them when we are able to up load if you would like.