The one inch aft rule is only a class rule. If you sail mostly in heavy air, moving the step further forward won't help you much-in fact it may make you overpowered. If you sail mostly in very light air, having the step another 1/4" to 1/2" forward would probably be a good thing. Of course, if one design is not a concern, you could install an adjustable step that would allow you to slide the step position forward for light, and aft for heavy.
An adjustable step would be great. Currently it's set up about 2" from the edge. I think the previous owner did that for the pacific cup race to Hawaii (downwind all the way). I get loads of weather helm and from what I understand, moving the step to 1" will only give me more weather helm. At this point I'm tempted to get a balanced rudder. The trade winds here are fairly heavy, 15-20 kts, usually more on Friday nights.
I've found that going to a #3 in higher winds not only eases the overpowered weather helm, but gives me about 3 degrees better pointing over, say my 130. Might be a little smaller, but it gives me a huge tactical advantage by pointing higher and being able to do those really quick tacks. 'Course, I didn't have a huge crew to stuff out on the rail and hold her flat, so thatlimited my sail area a bit, too.
2" is WAY back at the step. Having the mast that far back at the step probably makes any rig tune guide useless-the recommended headstay length (35'-10 1/2") is probably much too loose with the step in that location. You probably have a huge amount of pre-bend in the rig. I would recommend setting everything per the class standard (step at one inch back, heavy air rig tune at 40/40, headstay at class max). Then play with extra pre-bend by wedging the mast forward at the partners. I have found that the boat balances quite well upwind with those settings (and maxed out halyards and outhaul). What is your rig tune set at usually?