Hey Greg, I was looking forward to your input.
My engine has had its heads overhauled earlier in its life. What was done to them specifically, I don't know. The Potenziata engines do have a standard 9.5:1 compression ratio, tho what it is now I've no idea.
When I overhaul the heads again, new IAP phosphor/bronze valve guides, teflon seals, heavier duty valve springs and new exhaust valves (after reading on your site that Alfa used steel exhaust guides in the later heads (the d!ck he@ds

)), I won't have the heads machined unless I absolutely must.
Water Injection! What a subject!
I am really looking forward to seeing what can be achieved with water injection.
1 thing still nags at me, though. It's the potential for uneven distribution of the water to each cylinder, especially when the water flow rates from 1 or 2 nozzles starts getting higher and the air gets more and more damp/humid. I see the potential for the water to start falling out of the air stream. Maybe I'm reading to much into it.
But it did have me thinking about having 1 primary nozzle in the intercooler plumbing followed by 6 small secondary nozzles mounted in each of the inlet runners just under the plenum chamber. That would require a well made water distribution manifold to ensure each of the 6 nozzles flowed the exact same amount.
I looked at getting 2 of the Innovate TC-4 modules to data log the temperatures of all 6 cylinder's exhaust gasses right next to the heads in the extractor pipes, but $100 for each of the thermocouples (which do look to be very well made) did put me off

.
75evo, Greg is definitely the man to answer your questions.
But I'll add some thoughts on your particular situation.
I do think that potentially your cams could be a bit of a hindrance if they have to much overlap. As Greg said in his book, some overlap is good, to much will be a waste.
The 11:1 CR will be the biggest challenge. Water injection would be a must. If you haven't bought Greg's book on supercharging, then I highly recommend it! The section on water injection alone is worth the purchase price. And to give a little taste, water injection is less about cooling the inlet air than most people who sell water injection kits will have you believe. Intercooling will help reduce the knock tendencies, but it's no where near as effective as water injection is.