What he's saying here is you should buy shocks based on your actual measurements (not the 0-2" or 2-4" claims by a manufacturer). So get the springs you want in there and measure, then find the shocks that measure to fit. Any decent shock should tell you the collapsed length, and extended length (you can figure out the rest).
Fit means the shock is at 50% travel at ride height, ideally being the final stop when stuffed and being the limiter when extended. As mentioned before, compliment your springs with air bags in the front for the plow (air bags are just springs), and you'll have a better TJ overall.
Getting a proper fit though off the shelf will likely be a "get as close as you can". Many of us rebuilt our shock mounts/towers to achieve this as we've found it builds the best balance for the platform until you go really custom.