Houseboat Prop

[river rat 26]

Howdy you all. I put a new 90 evinrude on my boat (26' tritoon with a very heavy cabin built on top) I started out with a 16 stainless but could not get the rpm above 4000 so I got a 12 stainless and went up to 4500, I liked this prop it had lots of cup and pulled real good but I was still on the bottom of the recomended rpm range for the e-tec and no one around had any thing lower in pitch. I called BRP and the tech recomended a 9 which I ordered and have on there now. Got the rpm up to about 5200 which is good but this big ugly elephant ear looking aluminum prop with no cup has none of the things I liked about the 12 I had on there. That prop just pulled so much better so I called and talked to my prop builder and he is thinking of going to a 7 or 8 in stainless with the cup I loved on the other prop which sounds great but I need to know what you all think befor I spend this non refundable cash on this prop. He says when it comes in it will be mine with no returns cause it is custom. What will the change be going from aluminum to SS and no cup to cup, I can go as high as 5500 rpm so says the BRP tech. Thanks in advance.