I'm in the midst of installing a large stone resin shower tray; it's going
in an existing alcove where it will be a snug fit on three sides; the alcove
being as deep as the tray is wide (760mm). I've built the required platform
for it to sit on, topped with 0.75" marine ply, and now just need to lay the
tray down on a bed of mortar as per instructions.

Trouble is, this thing is obviously very heavy and I can't get access to
anything but the front edge to lower it down flat, ie parallel to the floor.
Having tried several 'dry runs', the best I can do is stand in front of the
tray, standing up on it's front edge, and then lower the high (ie back) edge
away from me till it reaches the deck. If there'd been mortar in situ, it
would have squeezed out the front all over my feet.... The tray is now 3 or
4 inches away from the back of the alcove, and has to be slid back into
place (which would bugger up the mortar bed still further).

Anyone done this before? I can't think of an easy way to do it, certainly
not without crippling nyself. How critical is the integrity of the mortar
bed - am I worrying too much about it? I sure as hell want it to be right,
though; I don't plan on replacing this tray in the forseeable future!

Thanks
David