Unless you're expecting to get shot, gauze with clotting agent is wholly unnecessary. Stick with regular gauze and carry a tourniquet (or be proficient at making a makeshift one). I'm sure you can find TQs for far cheaper in another place. Any type of arterial bleed in a remote area will be far better served with a TQ than combat gauze. Any venous bleed should be easily manageable with regular gauze and direct pressure. A SAM splint is nice to have but can also generally be MacGyvered. The only real "need" for one would be as ankle support, which can also be done with an ACE wrap, cravat, or a shirt. ACE wraps are also great for pressure dressings-two in one! Generally, my first aid kit when hiking is a couple bandaids, ibuprofen, and my blister kits. What you want on top of that is based on your comfort level to create a janky makeshift appartus. Always bring a fixed blade knife.
SAM splints are one of those fuck it items when they’re so light and compressible that I just throw it in the emergency kit for most trips. ACE wrap SAM splint everything you’ve mentioned is gold. Oh and tweezers. Learned that lesson the hard way earlier this year.
Answering wasoxygen's gear questions here: I'm going to be adding gauze to my kit for day-hikes, because it would have been REALLY useful to have last Wednesday. Other than that, I agree with the stuff you're saying - I can't hike that far in a day, and too much more would feel like overkill personally. That being said, I'm going to err on the side of caution now for solo hikes (which...I mean, it's gonna be awhile) and take more than I need as long as I can comfortably carry it. It's a good question, and I haven't put much thought into it yet! Boyscouts has given me an inflated sense of confidence in what I can slap together, so I think I'll need to reevaluate some things before heading out there again. Hear, hearAlways bring a fixed blade knife.