[mikesim (Mike)]

Hi folks,
I'm planning on building an observatory/shed in a dark sky location. Apologies if some of my questions sound a bit dumbass but I'm new at this and am hoping a few people with a bit of experience can help.

Shed will be built on a concrete slab (100mm reinforced). 4m wide x 5m long. The length will be aligned north/ south, with the roll on/roll off roof rolling off west (to protect from prevailing west/sw/nw winds). Shed wall height will be 2.4m high and shed will have a gable roof. Shed construction will be steel uprights (150mm x 50mm x 2mm box), walls lo clad 0.47mm and roof corrigated 0.47mm. Slab will sit on a topsoil/clay base.
The local shed guys have taken up the challenge and reckon they can put this shed kit together rated to category 2 (41 m/s) for around $7-8k (probably way more expensive than a do it yourself kit but I've had some other sheds from them and they seem to do a good job, plus I'm a bit of a novice with building my own buildings).

I'm getting a C11 on a cgem (when funds allow would like to get an AP1200 or PME mount) and want enough room for a reasonably sized refractor later on. Plan to do visual now and AP later.

I'd like to get a concrete pier put in to mount the CGEM C11 on it. I plan on staying at this location for a long time.

Hopefully someone can help.

1) Should I have the concrete pier poured with a rubber/flex join around the base to separate it from the rest of the slab to reduce vibration when walking on the slab and allow for expansion or is vibration on a 100m slab minimal (so I just get a solid footing poured under the base of the pier but its still all 'joined' with the rest of the slab).
2) Any suggestions as to the height of the concrete pier (am thinking around 1m)?
3) To allow for future mounts etc, what is the most flexible bolt configuration to have sticking from the top of the pier or should I just put in a top plate that would then bolt onto a secondary plate. The secondary plate would have all the necessary holes to bolt on a variety of mounts/ be interchangeable (not sure how the AP or OME mounts base plate compare to the CGEM).
4) Not sure what diameter pier would work (am thinking maybe 30cm?).
5) or is it simpler to just bolt down a steel pier once I have my slab poured with a section allowed for the footing (say 600mm deep and wide).
6) Any other helpful comments about my plan for the shed/pier (I've seen people suggest some pipe through the pier to allow cabling etc to be hidden).

Appreciate your help.
Cheers
Mike