I would be a little concerned about using that lift with the floor jack. I am not an engineer, but we have several on this board that may agree. It appears that there is alot of stress on that little jack. They are designed to lift relatively straight up, and rated accordingly. Lifting something, of considerable weight, that far from the lifting point on the jack, would require considerable strength. Consider that, by the time that you lift the tubing and chain from that end and angle, you have used a large part of the capacity of the jack, what is going to lift the engine? Ever try picking up a piece of square tubing from the end and holding it straight out? That is what that engine lift is trying to do. Then also pucking up an engine. It would have to be a 30 ton jack for me to feel comfortable with it.
The engine stand that is at the German site looks like it will hold up most any engine it needs to. I built one many years ago, using 2 1/2" angle iron, that I welded together to make tubing. I don't have the braces on it, like he does. Mine has had a complete 390 Ford engine on it and didn't budge a bit. If I was going to do alot with long straight 6's I would probably add bracing.