Leo, in your case, I will just add some dark green to an olive drab and eyeball the result. It should not be difficult to get it almost right if just for a canister. Good luck.
The JGSDF Type 10 usually has a brown and olive drab camo pattern. What does the kit manual calls out for the olive drab in the body camo? It looks like the XF-74 on the box art.
Edit:
I was wrong. The Type 10 uses dark green (XF-73) for the camo color. You may be able to get the XF-74 effect by adding a little dark brown to the XF-73.