Good morning all,thanks for your intrest Mark.I poured the slab some 15 years a go on a well tamped base, rebar in the footings ,wire mesh through out the slab and 6 inchs of concrete with the fiber mesh in it and there are no visible cracks.Today the hammer will be at my shop and the mounting process will begin and I will go with plan A ,mounting to sleepers and if Im not happy with that I will go with the concrete base. Best Regards