@LoopSki , I'd follow Chris's recommendations, but here is another data point for you. I'm 6' 165 lbs and am on a 65" Lithium. I was on a 66" HO S2. Initially the 65" seemed short not because it skied short, but because I was used to seeing more ski in front of me. I have not tried any Pro-builds, but based on your size/ ability I think the 65 is your number, and the Lithium is the layup to get you your -28... and beyond. This ski is no joke. If cash is an issue, keep any eye on the used equipment websites or watch for demos/blems. I too would like to hear from someone who has ridden both back-to-back.
Hope this helps. Good luck.