Re: whit oak uppers, I went RRA Varmint
I have owned an upper from WOP (before WOA existed) with a 1:6.5" 3-groove PacNor chambered for the 90JLKs and it was, hands down, the best across-the-course AR I ever had. Second place goes to the CLW 1:7.7" Kreiger that I had Frank build for me in the early 90s on a Bushmaster I had. For raw accuracy, it was phenomenal, shooting in the 1/2-3/4moa range at 300 yards with 69s or 80s. I prefer the more modern triggers (KAC, WOP/RRA mod, etc) over Frank's, but I have to give Frank a huge BZ for his ingenious way of making the AR trigger VERY good. John's pinned sights are awesome. Frank's float-tubes are best IMHO, but I used LOTS of sling tension.
In summary, buy and shoot from either in confidence.