thanks Eddy...more questions..

1, diagonals into corners why not?, ditto connecting 2 at the middle (sorry, I am one of those people that like to understand the why)
3 I get as it eliminates resonance... easier to draw symmetrically for this stage...
Bed support is not a problem... just no need to show for the frame development... it will be there when made
feet will be on a level pad and shimmed and bolted down

Re rails... I have been looking for some real comparative data.... (similar to the info on round vs supported rails on the forum) from what I can find... only looking as I wont be buying for a while... profile rails & bearings seem to be about 2x the cost of supported rails ( 20mm supported compared to 15mm profiled but I am guessing I will want 20mm? which puts it nearer 3x) ie I need info to justify the additional cost (in all likelihood I would end up that way anyway, these were the first 3d model that I found & thought "hell that will do for development, regardless of what I eventually use)