Well now
Couple of things to consider here
First you have a little more than an inch lift which is causing you problems with the tire size and backspacing you currently run.
Now the cheaper way is to install two extra top plates per side etc ( if you have enough space/threads exposed )as you have said. The problem with going that direction is that it is a band aid fix. The springs will continue to sag and in no time you'll be down another inch.
I would look at what this band aid approach will cost you now and how long it will last -vs- replacing the springs and shocks in front with OME or Ironman and starting over basically. Yes more expensive but in the long run a cheaper and better alternative if you plan to keep the KJ for a longer time .
Just something to think about .
I would assume that you may have caused some damage to your front shocks before you installed the bumpstops which also will speed up the sagging of the springs.
Just some thoughts, think it over and ask more questions / comments etc .
If you need help head west

I'll try and help you out!!
