Caveat: this is all theoretical and the only way to know travel limits is to measure at full bump and full droop.
Based on your measurements, the collapsed length of your shocks are front: ~14" and rear: ~13.75". This is close enough to the N3 listed on RC's website. Your exposed shaft suggests the fronts look to be pretty well biased but the rears might be on the shorter side, favoring up travel.
Shock Compressed Travel Extended Up (Exposed Shaft) Down Up Bias RC N3 1-3”Front (23169_E) 14.32 9.08 23.4 4.75 4.33 52% RC N3 0-3” Rear (23168_B) 13.57 7.83 21.4 5.75 2.08 73%
The fronts are fairly straightforward.
Front shock Compressed Travel Extended Rancho RS55239 14.43 9.41 23.84 SkyJacker Black Max B8516 (0-3" Lift) 13.52 8.78 22.3 SkyJacker Black Max B8525 (4-6" Lift) 14.52 9.78 24.3
The rears are a bit more interesting.
Rear Shock Compressed Travel Extended Rancho RS55241 13.51 8.16 21.67 SkyJacker Black Max B8518 (1-3" Lift) 13.93 8.78 22.71 SkyJacker Black Max B8528 (3.5-4" Lift) 14.91 10.02 24.94
Again, using Shock Math™ only, either the Rancho 239/241 combo or the BM 8516/8518 would be a decent fit for your springs on paper.
Okay I got to do a little wrenching, but only got the front done. I did get some numbers to work with to determine my options, well at least with the front so far. Looks like @imahnu may be correct, the b8525 looks to be the better option for the Black Max shocks. Here are some measurements of what I found:
Front full extension is 23". Full compression with no spring was 14.5", BUT full compression with the tire back on was 15" due to it hitting the shock tower on the passenger side. Looks like my bump stops are 2.25" to the cup, but 2" on the drivers side since it was no tower contact. I cut the poly ones that came with it to 2.5" just to give me some room. When I swap the front springs I will revisit and look at going back the OEM bump stops. All of this is with the 31" tires on canyon wheels. I have an extra set of steel wheels that may sport some 33x10.5 at some point. I may have to remeasure the bumps then.
I am interested to see how the back measurements break out. Going by just the front, the 239 or the 8525 both look like they would work well.