The service line running right down the middle of my planned tower location does somewhat limit my options but I've been getting some good suggestions. I think I have settled on using a mast base plate like the one pictured below anchored to a 2'x'2'x2' concrete pad right where the current mast base plate sits. I still have not found one I like in the USA that doesn't cost and arm and a leg. I can get this one delivered from the UK to here for about $165 (including the base plate and shipping) which is a lot more than I'd like to spend but it's cheaper than buying a MIG welder (but not nearly as satisfying) or hiring someone to do it. I just want the end result to be fairly easy and safe for my wife and I to raise/lower this mast assembly ourselves. I could always just remove the bolts, holler "fire in the hole", then "timber....." and down it comes.
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I also plan on standing up a gin pole using two of the 11 gauge galvanized pipes I already have (paired together and reinforced with the internal pipes currently at the pipe joints) to help lift/lower the mast via a pulley connected maybe 15-20' up the mast (TBD), a pair of pulleys on the gin pipe and maybe use my ATV winch initially to test it out. The pipes will be in about 3 feet of concrete and extend 8' above ground. I am replacing the existing 11 gauge 1-7/8" mast with 10 gauge 2-3/8". I will re-use the same wall mounts in addition to the guy wires.
My concrete needs are down to the mast base (still maybe 16 60# bags, 2' deep may be overkill for this simple mast application), the gin pole (5-6 60# bags) and one guy wire post (5-6 60# bags). The other guy wire mounts will all be attached to the rafters in the soffits. Oy, 26 bags of concrete is still a lot to hand mix.
A retired civil engineer friend of mine is mulling this all over for me. He's used to working with three dimensional, 40 lane freeway interchanges with lanes going every which way. I just hope he doesn't suggest building a ramp up to the rotor and bypassing the mast entirely. 
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