There are pics
here of my build, I used two bars and a stub tube of steel to drop the front under the gen, it was all mig welded together. Did two carts this way, the mount was pretty easy to do. I put a small piece of angle on the back mount to widen it enough. This is a G9 but yours may be similar, or may be able to do it similar with bars. I put the engine on a jack and blocks where I wanted it with clutches mocked up on it and clutch distance/offset I wanted (from stock clutch setup), then made the mount under it. Later I marked and drilled the holes, had to do that again when I changed clutch, and again when I moved to a longer belt. Making it movable would have been nice but really aside from a major changes I got into you should not have to mess with it. The footprint of a clone is not much different than a twin. Make sure you leave a spot for oil to come out, or be aware of the oil drains. My mount did crack the gen plate it must be cheap stuff, I later beefed it up there. The belt side takes more abuse. I used the stock gen and made a tensioner arm out of a lawn mower arm to hold the gen that bolts to the clone behind the clutch. So I had to make sure the gen belt lined up to the engine as well as the drive belt. Later made a solid tensioner cable that yours might not have, in a G9 they are under the gen pulley and holds engine torque under high loads. I built that in 2012 and other one before that both are running great yet, both use the stock mounts and have no vibration.