Redgwell's and Vit's max loads give about the same mv - a touch over 2,500fps. But with very different powder charges (44 and 41.7gn of N140 respectively).
With this discrepancy, I'd try an OCW load work-up, shooting over a chrony and stopping once I got to the 2,500fps mark.
I think Regwell tried three different 303's and didn't find a single load that performed best in all three. Which leads me to the conclusion that your rifle will tell you what it likes if you give it the chance.
Perhaps you could post any data and/or conclusions for the benefit of others?
Triffid