how to rate a hill

[fandacious]

We've discussed this a couple of times before. How difficult is a hill1 compared to hill2.

 

and this morning while mountain biking (and climbing a frikking steep hill), it came to me. its so simple.

 

I'm not a physics boff, but i can give it a shot. correct me where i'm wrong

 

Basically, start off with a constant weight, eg 70kg and then work out total work done (joules) moving that weight up any hills you want to compare.

 

if hill1 = 5000joules and hill2 = 4800joules, then hill1 is more difficult, regardless of gradient, distance, etc.

 

right?