Or any rigid with crane offload.
I know that in a perfect world you do not load/unload unless on level ground but if you had to,on a hill,is it better to be facing down or up?
Rear mounted crane btw.
I’m not an expert on this matter, but I would say face downhill, as the weight is on the back which is tilting forward.
all depends on the vehicle, I drive different crane vehicles most days of the week (agency) each one is different some thow a wobbly and wont lift pointing up hill, some down hill. Guess depends on what saftey sensors are fitted.
Rear loader face downhill if possible.
Front loader face uphill.
The pressure in the rams sometimes cannot handle the gravity. Slight inclines should be OK but only time and experience will tell you how much is too much.
Edit to add
Facing the correct way, if the load is too heavy the loader will simply stop when it decides that gravity is too great to move any further but if you face the wrong way, when gravity takes over the loader will lose control and the load will just carry on downhill regardless of what you do, it will only stop when it hits something that causes it to stop.
Basically, a runaway that you have no control over.
If you keep the load really low to the floor it’s not so much of a problem.
F-reds:
If you keep the load really low to the floor it’s not so much of a problem.
Can’t always keep it low to the ground though.
That’s alright until you are dropping onto someones driveway or garden, then you have garden walls, gate posts, fences, telegraph poles, lamp posts and all sorts of other wonderful things that you might wipe out if it runs away.
Including your cab 
True. But if that’s the case, that is why you have the “mythical lock out”. If you think there is even the slightest chance of it running away while going over something, get it to height, start moving to target, then surreptitiously give to STOP button a nudge.
whilst waggling all levers and muttering “damnit” with a pained look on your face “sorry guv, it’s just too heavy, it’ll have to go down somewhere closer.”
Hit STOP button again and pull her back in crack on with the easy life.
Still you don’t earn the Hiab drivers extra wedge like that, but it does keep life easy.
Not a block grab but similar.
This is what you do not want
youtube.com/watch?v=nrg-9uKNlFI