I used Hexrod to modify the properties of the original Martha Marie and held the stresses constant based upon the idea that it's the stresses that define the action of the rod. When I increased the line weight I also increased the length of the cast. Since I hollow my rods, I ran this one through the IBRA Hollow Rod Calculations spreadsheet. There were some modifications from the Hexrod numbers but they were very slight. This was just to test the effect of the spreadsheet on this heavier rod, I've done this with lighter weight rods and found no changes.
One of the effects I find with hollowing, in addition to the slight increase in the perceived stiffness of the rod, is that the rod tends to balance better than a solid rod which seems to lessen the amount of effort required to cast. My working hypothesis is that when the masses of the rod and reel before and after the balance point are equivalent then the swing weight of the rod is equal (probably not the correct term as defined by physics) and it seems to pivot easily around the balance point so less effort is required to start and stop the rod when casting. I try to get the balance point to be about 1" behind the winding check (in the grip under my index finger). In this case I couldn't do it without adding more weight to the rod around the reel seat but I've found that 5 weights and lighter can be made to balance pretty easily. Rather than adding weight, I decided to accept a balance point about 1 1/2" beyond the winding check. Not what you asked but you might find this interesting. My rodmaking buddies here in St. Louis and I have a running discussion on this point.