high mortar bed??

[phil on a fazer]

The higher the bed of mortar the less weight it will support, what i would do is go for the 40mm bed but lay 10mm bed with a slate or tile first then then place the another bed of mortar on that to get an over all 40mm, then place the slab on that. Doing this as a dab in each corner.

Thats kind of what i was thinking.....normal bed of mortar...then slate...then another bed on top of that for the slab to sit on???

Im trying to do the best job i can as i need it to last.