I would HIGHLY recommend having a 1/2" NPT full coupling welded right above the weld seam at the bottom, and then using a 1/2" NPT to 1/2" swagelock (compression) fitting and dip tube something like this: http://www.norcalbrewingsolutions.co...roduct140.html
I would then place the 1" NPS element fitting also right above the bottom seam, this will get it nice and low(lower is better), but high enough if you want to put in a 15" full false bottom. (If you use the wavy element, you may want to make sure you can still screw it in)
port for thermowell and sightglass.. you can use a 1/4"-1/2", half coupler and then use a nipple on a Tee to send the thermowell through and connect the sight glass to.
your radial separation/location is OK, but making it have your hose and wire runs short and direct is what matters after you keep the three at least couple inches apart from each other...... and keep all away from the vent holes in the bottom rim, in case you decide to use gas someday... just saying...