I think you are making a mistake going to a 4 blade on that aluminum boat. You would also need to likely drop back in pitch to accommodate for the extra blade.
The main thing (in my experience) that will allow you to run the engine up higher will be cupping of the prop. The more cupping, the better the bite. Shouldn't hurt hole shot (if sized properly), and will allow you to get the maximum trim/height that you can get.
In my experience, if you are happy with the WOT rpm's in your aluminum prop, if you get an aggressively cupped stainless steel prop, you would step DOWN 1-2 sizes in pitch to make up for the rpm loss. You yourself said she runs good with your current setup. I wouldn't make a big change (3 to a 4 blade.)
And the setback of the jackplate will certainly help you with engine height!!
These are all my opinions based on my 7 years of boating/tinkering. Best investment I have made on some of my rigs is a cupped SS prop.
BUT if you are going to be in an area where you are concerned with hitting things (hence wanting to lift the engine) I would say that aluminum is cheaper and more forgiving. And I am pretty sure Hustler makes a 4 blade aluminum prop. All things to consider.