Evening TZ collective. Has anyone got any advice on sourcing shroud screws for a 6159-7010 Grandfather Tuna?

My Tuna has one good original Ti screw, 1original not so good and 2 wrong-uns!

Im under no illusion about finding originals but what are the alternatives? Do any of the later Tuna variant screws fit, or are there any good aftermarket options out there?

Thanks all