I love it, it does anything and everything. It's my most used can. I have others, but I always grab the half Nelson. I use it on 308, 6.5CM, 300blk bolt gun, and I used it once on my 280AI. I can't comment on the performance for a 300WM, but the half Nelson is very effective. It's much quieter than my silencerco Hybrid which is about the same size and weight.
I'm not familiar with the Hyperion K, but the specs look pretty good.
I'd like to compare the half Nelson side by side to the Thunderbeast ultra 5 and Thunderbeast Dominus. The thunderbeasts have the same issue with needing a muzzle device, and as far as I know, the direct thread versions just have the device welded into the can. The thunderbeast are lighter, but not sure by how much when you add the muzzle device.
It sounds like you know you want direct thread, especially if you are familiar with the 419 adaptors. I just can't see the value of an adaptor for a hunting suppressor. At some point it just becomes a stack of thread adaptors and you're stacking tolerances and adding potential failure points. I love the 419 hellfire and self timing adaptor on my match gun. I'm not sure what other true direct thread suppressors would fit your criteria.
Let me know if if you have any other questions or want any actual weights, dimensions, pictures, etc on the half Nelson.