I think if you are going to duplicate the design of the 04 CPS you need to include the oil groove. I'm having trouble understanding the concept. With the 04 CPS the oil goes in above the lower bushing and the oil groove forces it between the shaft and bushing.
With the mod tkki made (please correct me if I'm wrong), the oil goes through the bushing? Otherwise up the existing oil port and then hopefully down through the shaft and bushing? Either way I think the groove plays an important roll of generating a path of least resistance for the oil to travel.
The way the older type shaft has the groove moving the oil downwards would be optimal. You could also groove the bushing to do the same thing.
The way I have it now, there the two holes opening up into the bushing, like the FOGMOD. There is no "opening" to move larger volumes of lubrication down that shaft. But I think that the amount of oil that goes up the flat spot is significant. Proof of that is I reinstalled the unit the other day, but I forgot the gasket. There was a lot of oil leaking out of the flange area. I was quite surprised.
Speed, I just talked with my machinist, and he says he can do the job if you want, but he warned me about the costs. The machining part is cheap, especially if you don't pull out the bushings. But the Shaft hardening is expensive, and that he cannot do that in house. I think the company that he uses is KC Jones Plating company, but there are many firms that now offer nitriding service. He suggests that you take the unit to a local machinist, and show him the pictures of how and where you want the flat spot done. All they do is lock it into a Vice, and take off a small amount with a milling machine. It only takes 10 minutes to do.
But I would listen to Willy. None of what I'm doing is "optimal." I'm just fooling around. There is obviously a better way. And I would wait until that is found until you started major modifications to your unit.
The hard part is to have owners out there guinea pig their Motors/OPDA units for research. All of the work I've done so far, along with the cost of the units that I've bought, which exceed $1K, is getting past the point of reasonable return on investment.