Have nothing on a "Grim Reapers" sqn, sorry.
Name rings a bell though, and for some reason Op
Fire Dog and 9 Sqn come to mind (Malayan emergency) - that would be around the date of John's picture - on their way back. Mind you 617, 12 and 101 were also in that set-to, and more including the RAAF Cans and the RNZAF (with a "loaned" sqn of B.2s from the RAF).
Don't think it was the H or A tests - Op
Grapple or the previous Op
Hot Box. The latter only used two Cans - WH710 and WH962. Op
Grapple used dozens of course in 56 - 58(ish), but their out and back routes were generally via Hickam and the states. probably wrong though.
I'll ask around but I hope someone here can fill in the details.