decompile the original hg map and copy and paste them. thats what i did anyway. you can edit the guns that they drop if you want but i think the original mappers picked good ones.
I remade all of the crates my self, using the same drop method. I wanted different tier crates on hg_warehouse - some they only spawned pistol, some with smgs and others with a rare chance of a shotgun as it's a CQB map. If you look on the game banana post for hg_warehouse it has the loot tables in the description. You can use them if you wish.