Just to clarify, the 6.2m will certainly still be well within the sweetspot of the ST115 for 80kg, just that if you average the 6.7 and 6.2, the ST that fits even better (moreso if you consider the lumpinesss of the Bay in 6.2 conditions Bay) is the ST104.
I guess one thing we didn't really identify is what style of riding you anticipate for the ST104 (replacement). If you're really using the SuperX potential to blast and jump and play around a lot, and riding it mainly in powered conditions then ST is the better choice for "easily" dealing with chop at speed - and in 6.2 conditions would be sweet- , but (especially if your mid size board creeps up the size/down the wind range abit more) if you're looking for more range and potential "race" performance for next season from the board in that slot, you might also want to think about iS101, which will definitely carry the larger 6.7m and even V8 7.5m nicely, while still not being too boat like for fun in 6.2 conditions (but not as jump proof as the ST). Yes, it is a more technical ride than ST, but especially as you would move (earlier) to the K97 (if that was the choice), the iS101 would be in practical limits..
Don't under estimate (without trying) the almost freeride ease of the iS101 when sailed in anything easier than "extreme 100Lt slalom" conditions. Again, demo should not be hard to arrange - and would be worthwhile even if you don't intend to go that way..
K97/80kg/Bay sweetspot peaks around 5.0 to 6.0m, certainly 5.3 is near the peak, but 5.8 is also exceptionally well suited (even for heavier guys) and 6.2 m is without question still absolutely within practical and fun K97 range... So you can sort of see where that is heading..
Would running with footstrap in the forward and inner position as I currently do help with control on the bay?
Running Forward helps calm the board across chop, giving a setup that usually allows you to "power on" more over the rough stuff; the inboard setting gives a more reactive, moves type stance, whereas the outboard stance allows more leverage over the board/fin - which gives a more locked semi slalom stance. This can assist control in rough conditions, but make the ride more committed and demanding; with inboard straps you have less leverage over the board but the ability to ride (control) it in a more fluid, reactive wave like manner. On the Bay, in lighter conditions generally the outboard semi slalom stance works best, but as it chops up, the inboard is usually not a lot less effective, while being a lot more fun !
Also the 2007 model ST104 states a lower size range compared to my 2005 model. Would the 2005 get going before the 2007 using a 6.7m based on stated ranges?
Those change more reflect our ongoing revision of the ideal "sweetspot" for each size as the model evolved, rather than significant variance in the planing threshold. If anything, with the newer flatter rocker the 2007 ST's will be going a little earlier.
If Warwick's got the K97, do the demo - and the iS101 while you're at it. One evening in decent rising seabreeze at Elwood should give you the verdict. At least for Round 1 !!
Cheers ~ Ian