I would encourage you to get comfortable with a tool and consumable loadout somewhat, at least to try to keep them in the same slots and change your keybinds so you can quickly switch to a vitality shot or a melee weapon without having to scroll.
You can make loadouts just for those, but this game’s UI is a buggy mess and the UX is guantanamo bay tier so I would wait with that until you feel ‘rich’ and always able to buy everything you like, so you don’t get gear fear and frustrated with the fact that the game doesn’t automatically use your contraband items.
For weapons, it’s up to you. The Martini Henry is a decent gun, though I would say it’s outclassed by the Sparks in terms of damage and by the Springfield in terms of special ammo. There are challenges in the game for making hunters bleed, or using specific weapons, etc. so being able to make use of multiple guns is useful. Challenges give bloodbonds and battlepass points.
If you feel like you want to play something varied one day, you can try out different loadouts, and if you feel like you want to get good with one gun another day, you can do that too. In the end, it’s about your enjoyment.
Whenever my GM says I get to play I know it’s gonna be fire.
I’ll play fucking uno if that’s what he’s running.