Ok... went and did it. I was just going to do it so I'd remember exactly what happens, but after I got it apart I decided to just take pictures. I'm not a photographer, but the pictures will hopefully be illustrative enough for their purpose.
The major thing that I do differently from what you are trying is that I take mine down to this...
first step is to sandwich the sides with the spacers and blade stop in place
At this point I put the "action" springs 180 degrees from each other and put the correct one through the hole to the other side. Then its just a matter of turning the axis pin perpendicular to the handles and putting the springs back in their home
you will end up with this
next I put the pivot in place so that it is flush with the inside of the liner
put the first washer over the hole and push the pivot through a little more
next comes the blade, leaving the gap between the blade and the opposite liner
slide the other washer between the blade and the liner... you can use the pocket clip to help...
ok... at this point if you followed my directions to a T... you messed up, because I messed up. I forgot to put the handle scale on the pivot first. If you happen to do that too, just pull the pivot CAREFULLY and you'll be left with this...
now you can just add the scale, and push the pivot back through and you'll be here
Pop your other scale on, put all the screws back in, reattach your pocket clip then you're done!
Hope this wasn't too long and/or boring. And I hope it helps. The Rift is one of my favorite Benchmades. I bought mine after I graduated Basic Training and have carried it every day for the last 2 years.
Insert gratuitous knife picture...