This is my take on the Daystar upper strut plates.
The Daystar upper plates are used to put the shock travel back into safe operating range. The top plate does nothing but hold the strut assembly together, right?
Take my lift for example....I run OME front springs OME shocks with original top plates. Now, say I put in the .75 poly spacer under my set up I have now...this will increase the height of the strut assembly....pulling the shock cylinder farther out closer to it's fully extended limits....then when you get into a full droop situation, the shock is closer to nearly full extension..and boom you get a f**&^& shock...now if I then replaced the stock plates with a Daystar plate, the shock mount is effectively lower by 1.5"(or whatever it is, I didn't measure it) and put back into a "safe range" of operation.
In theory, you could have a spring 4ft long, as long as the shock moves in the proper range of travel....then bump stops come into play.
Did that make any sense??

Again, this is just my opinion.