Having a tall model, but a short camera feels... Unusual.
While I would normally understand there being issues regarding a higher camera, the mod MorePlayerModels had a workaround I felt was perfect.

What MPM did, was make it so if the camera would normally be inside a solid block (not torches, signs, grass, etc.), it would push the camera lower back to 2 blocks. Blocks that would otherwise normally be out of reach instead can't be broken, as they would just be replaced if on a server due to being out of player range.

So what i'm suggesting is an option to change the height of the first person and third person camera, that functions similarly to how MPM did it to be either higher or shorter than the normal camera and not clip inside of blocks.

By the way, thanks for making this mod. There isn't a lot of good mods that let you modify the player model, and while getting the model to show up online can feel a bit clunky at times, it does work and it's great.