please

i've dug a big hole to make a patio at the bottom of the garden to stand a shed on etc.

the hole has an area of 11 square metres (118 square feet), and is 150mm (6 inches deep)

i intend to put hardcore down and compact it to a thickness of 100mm (4 inches) before mortar and then concrete slabs. does that sound about right?

the soil is what i would call normal soil, not clay or sand. what kind of hardcore do i need, as i've seen lots of different materials around?

something like this?

http://www.wickes.co.uk/invt/220082?...9bQPNXrg%3D%3D

how many of those would i need for that area and depth - a volume of 1.1 cubic metres (39 cubic feet) when compacted?

thanks for any advice