Glort, like mentioned, it is a long way from Dursley to Rakjot:) If you have seen any vids of how these are cast and assembled, you would fully understand why each listeroid is unique... Mine runs about like 38's, AFTER I balanced it. Before balance, it would slowly creep across the floor and spin in a circle. After balance, with It set on 3/4" pipe rollers on the garage floor will only move around 15 thousandths of an inch back and forth, even with 3KW of load on the generator. It has spoked flywheels, that were actually intended for a internally balanced engine(no cast in weight). SInce I was planning on balancing anyway, it was no big deal. I think I added 17oz of lead on each wheel.
Another thing that muddies the waters a little is that each of these unique listeroids gets a custom designed and fabricated base(most put together by us non-engineers). The overall movement is the sum of ALL the forces applied. Theser engines have a massive power stroke, and a resulting massive torque input to the frame from their base. Any spring or flex in the frame, can absorb, store and release this torque energy unpredictably. This torque energy applied to an uneven floor/frame interface can easilly translate to a rocking motion, and next thing you know you got a walker that appears to be jumping all over the place... On a reasonably balanced engine, a little bit of freedome can actually make them appear to run smoother as these forces don't get anything to push off of and are absorbed by the mass of engine, frame and generator head which is well over 1000# on a 6/1-ST5 combo.
As an example, I bought a chinese single with a 10KW generator head. this sucker is easilly heavier than the 6/1 generator. Bare frame setting on the concrete, and it walks across the floor and visibly vibrates. Add a little block of 2" thick ethefoam under each corner(squishes nearly flat), to provide a little isolation and set it on 4 points, and it sets rock steady with no visible movement even under load...
Yes it can be done, but getting your brain around all your particular variables can be quite a learning experience...