OP
i didnt know the poly had the same foot print i assumed out side would be larger and not fit in a wbcThe Abelo 11-frame National poly box has an identical footprint to any wood National.
As for rectangular WBC boxes, you'll have to add a few strips of wood round the rims to size them to match square National 460mm boxes.
the wbc super i was thinking of doing one box so when / if i run out i can use national the draw back is i will probably run out of lifts as well