Have nearly 100 of these helpful wee things which are surplus to requirements. They cost me Cdn 10¢ each, so I can send you however many you want for the price of postage.
Photos below show these installed:
➢ 2 on my Raven, side-by-side with two M4 x 5mm barrelhead grubscrews, for comparison
➢ 2 on my Easy-set
These grubscrews are stainless steel, and the socket in the head takes a 2mm hex Allen key, same as the standard Rohloff item.
The 6mm grubscrews stand about 3 mm proud of the surface of the connector, making connection/disconnection much easier than with the standard item. On my Raven, I’ve installed the grubscrews on the outer sides of the connectors, so that they don’t foul each other.
A set of four would work nicely on two pairs of connectors. I'd suggest a kit of six, to allow for escapees.
Send me a PM if you’re interested, with your postal address. I have a PayPal account, so the cost of postage is easily transferred.