Not the outer basket - it's the inner one that's the problem. The outer basket is already made of something fairly hard - you'll see marks in the coating where the clutch plate dogs hit it, but no real depth to them. It's the other side - the bit in the middle of the clutch that the steel plates mate up with - the steels are hard, and that bit is soft aluminium alloy - that's where the notches are. Have a look at your original post on this thread - the 3rd photo, in the top right corner - you can see the notches there. If you can find a way to fit something harder in their place, it's worth doing (and maybe offering a service to other K12/13 owners - there's a fortune to be made in dodgy clutches out there!).
On the 72mm pin, I wouldn't bother doing any more work to it. We don't need masses of oil on this clutch, just a little bit (think about the drain holes you machined -they wouldn't be needed if there weren't already enough oil getting in there). Plus, that way you don't have to worry about not having the uprated oil pump (it's actually just the same pump - BMW simply changed the drive sprockets from a 25:25 ratio to a 26:24 ratio to make it run faster!)
The uprated bearing is definitely worth doing - best improvement I made on my clutch. I found one for £15, but that was quite some time ago - the same place now charges £31! If you want one, the item to look for is: INA NK35/30-TV-XL Needle Roller Bearing (make sure it's made by INA, and make sure it's the XL version - higher load bearing = longer life!). It's a 2 minute job to knock the old one out and this one in - it's not much of an interference fit.