How can I evaluate which userlevels the currently logged-on user possesses?
For this you can use 4 DWORD variables of the system driver. Create these variables in your project manually or use the system driver wizard and select the category password.

All the four DWORD variables represent the 127 user-levels which the user possesses which is currently logged on in the runtime.

the first DWORD (32 bit) shows the levels 0-31. The second DWORD shows 32-63, the third 64-95 the fourth 96-127.

e.g. if "user1" has userlevel 1 and userlevel 3, and this user logs on in the runtime, the DWORD(1) would have the value (binary): 0000 0000 0000 0000 0000 0000 0000 0101 or decimal 5.

You can use a binary reaction matrix and link it to variables in order to evaluate which levels are active.