470R:
The 400gr Taipans are bombs on pigs, very deadly! I reckon they would perform similarly on large deer. Surprised to hear the Woodleigh didn't expand on a Sambar stag: I could be wrong, but I get the feeling that Geoff has been toughening them up a little since his big move into the US market. Lots of yanks pushing the velocity envelope, especially with single-barrel rifles, and demanding a tougher bullet. Main competition comes from Barnes X.

Here's an example: 650gr .577 BP softs at 1650 fps mv. On the left, bought several years ago, on the right, bought last year. Both retrieved from buff at ~30yds, under the hide on the off-side.

DD:
I use .338 cases necked up for .416 Taylor brass, my Davern dies have a long tapered expander, straight up in a single pass, never lost a case! I prefer thin necks (last longer), but you will get an extra couple of grains of powder into a necked-down .458. Dunno why that should be, but I guess its important if you really need to chase 2400 fps.