Should not be a problem getting 2, 2.4 and 4mm for the common even numbered BA cap heads which are 6, 4 and 2BA, Someone Like Model Fixings have key, tee wrenches and ball ended drivers in those sizes
That is what I use and they all fit, if not go looking for 5/64, 3/32 and 5/32" again not too hard to find as are 0.9mm (0.035inch) and 1.27mm (0.050inch) which fit BA grub screws. Same supplier does them too.
Edited By JasonB on 17/11/2021 13:18:16