Speaking generally in the Tent site category the tent sand/coquina pads are bigger in loop 2000 than in 1500 (the other Tent loop) and even the Full loops 1600-1900.
Little bit of backstory: loops 1500-1900 (mix of current Tent and Full sites) were added to the Fort a short time after the first 6 or 7 loops opened in 1971. At the time they were added, they were all the same so today the basic difference is 1500/Tent doesn't have sewer and the the other 4 loops do. But GENERALLY speaking, tent pads are similarly sized in those five loops.
Loop 2000 (and other loops on that side of the Fort) were added in the 1977 and 1978 timeframe. They learned/improved on the previous addition and thus their tent sites are GENERALLY speaking larger than 1500-1900. Loop 2100 was part of that at the time but was later converted to cabins and then in 2015-2016 converted BACK to RV/Tent sites but with generally smaller pads. 2100 is now classsed as a Full but with really small tent pads. It wouldn't be a good fit for you.
Be forewarned that loop 2000 feels a little bit further away from the Core area of the Fort. Although it has 2 Comfort Stations for nearly 70 campsites and its own internal bus stop, it can feel crowded at times.
If I were you, I would ask for a 2000 site right near the entrance of the loop (starting at 2001, 2002, etc and the highest numbers 2067, 2068, etc.) since both are near the entrance and a Comfort Station meaning a shorter walk to most areas (the bus stop at cabin loop 2200 is really close). Or get a site in 2000 on the outside of the circle with numbers around 2034 or higher (which is near the 2nd Comfort station in the loop). Those outside sites back up to the group campsite Creekside Meadows and you can walk off the back of your site and skim Creekside Meadows and cross a bridge across a ditch that will put you in loop 900 (Premium) which is across from the Meadow TP.
TLDR version (Too Long Didn't Read):
For the biggest tent pad to accomodate two tents, loop 2000 is the go-to. Full loops have a plus in their favor on location but you can offset that by being in either of the two locations in 2000 that I stated.
Bama Ed