I've used wooden decking nailed with a spacing of 9mm - this allows free circulation of air within the telescope area plus it allows the air pressure inside to equalise and prevents the roof being blown off/sucked off - whatever.

Piers are made by the local engineer out of heavy duty 6" boiler pipe, they are mage to take the Losmandy G-11 and are the same height as a set of tripod legs. They are set into a concrete base and attached by 4 20mm prethreaded rod set 500mm into the concrete. They have a nut top and bottom which is used to level the pier then everthing is locked down.

The concrete base is simply a hole approx the size of a 44 gallon drun dug down till you reach your armpits (so you can pull yourself out)- set 6 reinforcing bars around the circumference and fill with concerete to ground level, I then cut the top of a 44 gallon drum, take out the centre and then use the ring to set the height of the concrete, fill with concrete then vibrate the pier with bolts attached into the concrete.