Every rifle is its own animal, but 95 - 97 gr of H1000 with a 225 TTSX is a sweet spot for mine. Lapua brass and F215.
Velocity is 3050 - 3100 fps in a 26" 1:10" with ambient temps in the 60's as a reference point and 0.003" of neck tension.
That is a less than max load, but accurate and pleasant to shoot.
My other TTSX loads all show best accuracy a bit below max.
Either the H1000 or Retumbo should provide good results with the Barnes 250 and 265.
210 Partitions never did anything worth fooling with in my 338 Lapuas, much prefer the Barnes 225 for a lighter bullet.
Start with the H1000 and 225 Barnes. It is a good combo with lots of versatility.
Here is a link to Barnes' data.
http://www.barnesbullets.com/files/2017/08/338LapuaMag.pdf