many Alembic have this problem, thank's Alembic.
I too I can't choice light gauge, I must run with 105-40, 105-30 for my 5 strings and 80-30 for my tenor.
If trussrods are loose, like on my SC deluxe, the only thing you have to do is to elevate (put higher) the bridge and wait 1 week. You adjust after a little. Don't forget to put some oil on the fingerboard, it protect against humidity and dry.
I did one thing when I was on hollidays: you elevate your strings with the bridge very high, you put a big book (3.93701 inches) on the middle of your neck under the strings, you really loose completly your trussrods and you wait 2 weeks.
After you can adjust the truss rods. Mines are not more loose now.
Good luck
PS: maintain your bass at constant hygrometry in a dry place and out of his case.