Engine stand mounted slant 6

Look at your photos. The bearing for the stand is nearly in line with your crank. You want the bearing (pivot) of the stand up higher on the engine. As said earlier, if you move the sliding mount adapters so that the stand plate puts the pivot "up" in line with the camshaft (V8) this makes things less top heavy.

You can rig your engine hoist / come along to hoist the engine and reposition the stand. This might be easier said than done, don't forget that you can turn the fingers on the stand "any" direction so for the top two it might be helpful to point them "down" for the top bolts with the bolt heads "down" and the plate ends "up."