Well I did manage to get to the range on Sunday, although it was very windy, I still shot soem respectable groups and pleasing velocities with my 416 Taylor.
Loads and velocities below, my rifle is most certainly different from anyone elses, so use these loads at your own discretion.
All loads used Hornady 458 cases necked down, Federal 215M primers, Gator-checks and LBT Blue lube.
All groups at 100 metres.

350 grain LBT WFN
25 grns Trailboss. 1433 fps, lousy accuracy.
25 grns Blue Dot. 1539 fps.
38 grns RE 7. 1544 fps. 1.5" group, 3 shots in 0.630".
45 grns AR 2206H. 1516 fps.

370 grain RCBS FN
25 grns Blue Dot. 1526 fps 1.050" 5 shot group.
38 grns RE 7. 1552 fps.
45 grns AR 2206H. 1558 fps.

410 grain NEI RN
25 grns Blue Dot. 1456 fps.
38 grns RE 7. 1505 fps.
45 grns AR 2206H. 1556 fps. 1.5" group.

I normally aim to get my cast bullets out at about 1500-1600 fps, and these loads were in the ballpark.
I'll keep playing around a bit to see what else works.

DC