Looks good for sure! Just an idea for concerns on the tub and edge of the rack... You could attach/screw/affix a piece of material to the edge of each shelf that you could rotate up or down. In the down state it would be the span one level and come down right in the middle to prevent the tub from moving outwards. Does that make sense? Think of clock hands and how they rotate, swing the latch up to pull a tub out and then swing it back down to "lock" the tub in place?

Anyway congrats on a step forward!