Eldritch Theurge Glaivelock, viable?

[Dusk Eclipse]

Sanctum spells are considered to be 1 level higher than normal when in your sanctum and 1 level lower when you are not. Thus, in your sanctum, a 1st level Sanctum Magic Missile is considered a 2nd level spell.

Doesn't that means that I need to level up inside my sanctum? though OTOH this a setting where all landmass are floating above an endless sea and airships are the main if not only way of trasport between such landmass, so making our airship my sanctum would theoretically work....