hmmm. either youre not understanding the original post or im not. i took it to mean he was having trouble getting 90lb dumbells onto his shoulders to do some overhead db presses. if that is in fact what he meant, he certainly should have no trouble doing 95lbs behind the neck.
now, for advice to the OP, i think the best/easiest thing to do is pull the dumbells so they are leaning just above your knees and then sit down so they are resting on your quads, pretty close to the knee. then you just kick them up. i think a lot of people have a "stronger side"- for me im right handed and i feel better kicking the DB on my right up first, and holding it in place above my shoulder while i kick the left up. btw- yes, with a 90lb dumbell in my right hand, my left kick is a little sloppier, always gets the job done though. i definitely feel you on the problem though. those 95's and 100's are just around the corner for me, and im more worried about how the hell im going to kick them up than how im going to press them.
also- in case its not obvious im talking about sitting on a low back bench/chair, which i think is a must here, unless youre 340lbs and the 90lbs db's feel like 30's would to everyone else.