The wings, especially at the tips, are indeed the hardest part; you have to get those first, just as soon as you possibly can.  The tails are next.  After that the body feathers pluck easily.  
We did 5 birds yesterday and mostly dry-plucked all of them, but we did scald the wings.  Also the little feathers on the shanks are much easier if scalded, you just rub them off, and it's the only way to peel the scaly skin off the knees. 
My wife hates the smell and stickiness of hot wet feathers, so prefers dry-plucking even though it is slower.  So for us the best compromise was dry-plucking the bodies, then scalding for the wings and shanks.  
If there's a next time, we'll make or borrow a plucker, and scald the whole birds.  I think scalding makes the pinfeathers easier to remove, too, and these birds had a lot of those.