tub install

I am remodeling a bathroom and installing a kohler cast iron tub...I have 1/2 plywood on top of 5/8 tongue and groove subfloor ...planning on 1/4 hardibacker on top of that which will be butting up against the tub...tub is sitting on top of 1/2 plywood my questions are... I am concerned the tub might be resting on the apron as well as the feet...should I now shim up all four feet ???so that the apron is raised off the plywood...
thanks in advance
gppg

Common practice is to have the tub sitting on a ledger board, fastened to the studs and on the apron.

John

Some tubs do NOT have feet, Kohler does, but if the floor was level, and the tub is level, then it is sitting on the feet, NOT the apron, but you should also have a "ledger" board under the rim at the rear to eliminate, or minimize, separation between the tub and the tile.