Thanks for the vote of confidence Matt
Rick, Sump has a capacity of 25gals + the 90gals DT= 115 gals total volume water, if we reduce sand, rocks you get around 90 gals overall if not a little less.
It's always best to get a skimmer which has double the capacity of your water volume.
There are great brands out there, from proper experience I have used Reef Octopus (and lots of them) without any disappointment.
ASM as Jason stated above is also a great brand, try looking at one who has been around enough time so you can always have support or warranty, in case of Reef Octopus they have an almost change without asking policy.
Back to topic, if you were to look for an Internal Skimmer, I'm guessing due to the size of the sump, the skimmer you need to fit in there has to be size efficient, Reef Octopus has the
Super Space Saver series, and this is the one I would recommend for having the best skimming efficiency for your system, which at the end, is double the size of your water volume.
Super Reef XP2000Space Saver | CoralVue
The footprint is 10.4" x 9.5" which I think will fit in your sump, and the optimum height operation is 5.75" which I think the water level in the sump will operate (This depends on the baffles height).
It would be great to know how much space you have in the skimmer chamber in the sump so you can be sure this type of skimmer would fit.