First was UAL825, which was at Gate 81, and was flown with an A320 (AirbusX).
This is set at 30 meters max allowable wingspan so yes, it's normal that it would be reported as too small by GSX, becaus the A320 has 35 meters wingspan.
As I've said in my previous message, you can use the "customize airport position" option to set it to a radius suitable to your airplane, which can be done with the small airplane symbol button in the editor. You can do this for multiple parkings at once, for example if you select the whole Terminal 8 node in the editor and change the wingspan size, it will be set for all parkings at Terminal 8 at once.
Second was UAL1636 out of Gate 49A.
No, this is a fairly large parking, and is set as with 62 meters in radius, plenty of space for an A320, so you shouldn't have seen the too small message. I just tested it, and it doesn't, all GSX services are available here. If you saw the "too small" message here, it's possible you have another AFCAD from another product in conflict. As I've said in my previous message, you can check which AFCAD is in use by GSX, using the "customize parking position" option, which indicates the AFCAD used.
where can I find the manual?
the manual can be found in 3 different ways:
1) like any other windows program out there, the installer has created an Fsdreamteam program group under the windows "Start" button, which contains just one entry, which is the link to open the GSX manual
OR
2) by clicking the "Open Manual" button on the Addon Manager, after selecting GSX
OR
3) by browsing your files under the fsdreamteam\couatl\GSX folder, under the main FSX folder