Use gridsnap 32, check the tr_hlaalu_test cell in the attached esp. Load with addon.
https://www.tamriel-rebuilt.org/releasefiles/tamrieldata-tr-addon-4266

F = Foundation
L = Lower
M = Middle
U = Upper
T = Tower
R = Roof
    Alc = Alcove
    Ent = Entrance
    Idt = Indnt = Indent
    Pln = Plain
    Blc = Block
    E = End (filename only)
    Cnr = C = Corner
    CL = Corner Left
    CR = Corner Right
    W = Wall
    Tn = Transition from one roof height to another
    Dub = Double sided walls
    DbLip = DiLi (Filenames) = Double sided walls with a lip on the outside

RS# = Roof Surface
RSX = Roof Surface Transition between different heights
    TL = Top left
    TR = Top Right (no tamriel rebuilt jokes allowed)
    BL = Bottom left
    BR = Bottom right
    Rmp = Ramp