They don't use crushed 1/2"-3/4" granite/rock in the cement mix ? That would add a lot of strength. Compacted 1/2" granite and granite grit is a good base, but you want it 6-12", depending on what is underneath (deeper if is sand).
(Some areas of the US don't have gravel either; they use crushed rock or old crushed concrete.)
Typical cement "flat work" around here is 4" thick. If it is going to carry a heavy load (trucks) it might be 6" thick. Rebar is not common, unless you really need extra strength. Wire mesh is more common.
The best solution requires a template of the foot of the lift post. Dig a hole where you are going to place the post >6" larger on all side of the foot and 2-3' deep. Bend some rebar to re-enforce the hole. When the pour the cement insert your mounting bolts using your template as a guide. The mounting bolts need to be >12" long ans should stick out above the finished cement about 2".
If you are unsure of the final placement of your lift, you can cut the floor and dig down after the floor is finished. For that matter, you can just use well compacted crushed stone as the floor, but the piers to mount the posts would have to be 4-6' deep and have rebar.
