Multi Floor Ceiling Height Adjust in Builder?

Is it possible under DOOM Builder 2 or GzDOOM Builder to select a bunch of sectors at once and auto adjust all ceiling/floor heights by 128/256/ etc.?

Select your sectors in 2D mode, open their properties, then enter ++128 in the floor (and/or ceiling) height field. This will raise the floors (and/or ceilings) of the selected sectors by 128 pixels. --128 to lower them.

In 3D mode: select the surfaces you want to move, then use mouse wheel to lower or raise them. Holding shift while doing so will move the surfaces 1 pixel at a time (instead of 8 pixels).

In recent versions of GZDB there is a field in which a value can be entered
when ceiling/floor should change by the same amount.

Perfect, thank you!

You can also select a bunch of sectors in sector mode and use the mouse scroll wheel to move the ceilings/floors up and down in 8 unit increments. Hold ctrl for floor and shift for ceiling.