DLR does not make this information public. An estimate is approximately 85,000 for DL and 50,000 for DCA. So 25% of that would be a little under 34,000. People are speculating that DLR will open at around 20% capacity, though.
Note: The only reason I say that the fire code capacity is >100K is because I remember working at
Disneyland during the summer of '96 when the Main St. Electrical Parade was "glowing away forever" and for a few days, park attendance breached 100K. Almost every other day was in the mid-high 90's. That was 25 years ago, so take with a grain of salt.
I want to clarify something here. There is a MAJOR difference between capacity and attendance. Disney has quite often hit "attendance of 75-90K, but that counts all entries. CAPACITY is very different. It is based on open rides, open walkways, open stores, open restaurants. In 2002, full capacity in Disneyland was about 58K (I had an in), but they did add SW:GE since then, and I would guess that would add about 16K. For estimation, let's say it is now 75K. DCA in 2002 was about 30K. However, we have cut out the area in BugsLand, so we need to deduct 5K until Avenger's campus opens. Now, while I give Disneyland credit for the full 75K, we need to remember, several large restaurants are closed (ie Hungry Bear, Rancho, Pizza Port). If they have the seating areas closed, this will deduct capacity for those areas.
But let's just mess with the knowns. Disney is going at 20%, so figure Disneyland will have a capacity of about 15K, and DCA will be about 5-7K. If I have listened correctly, TOD was topped at 7K. Now, for this who think "WALK ON!!!" Remember, they have cleaning issues, spacing issues, timing issues, and lower staffing.
With the soft openings, I think they will get some of the bugs smoothed out. I still expect April 30th to be a mess, but I will enjoy it!!