If you want to stick with the stock MC but use a single brake hose, you can get a banjo bolt with a pressure switch incorporated. I think Mike's XS has them, as well as the guy on here (pampadori) who makes hoses for members. As far as the inner bore, you're right, the one I used is a little smaller than stock, but close enough that it shouldn't be too much of a difference.
On piston coating, I think there are three types you can get. I'll see if I can hunt up Bob's description. I'm definitely not qualified to say whether it will make a huge difference or not, but he had the pistons already and the price was reasonable. If you have to spend and arm and a leg to have it done over there, I wouldn't worry about it at all. I think one of the coatings helps to shed oil from the piston skirts, allowing it to return to the sump at cooler temps, and another coating helps concentrate the combustion heat correctly, or something like that. Then there was a third I don't remember... Ok, found it, here we go (I got the first two coatings):
1) Dry Film Lubricant (DFL), is a lubricating fill applied to the skirt of the piston that reduces friction, inhibits galling and seizing and in some instances can aid in dispersing heat. They are slippery and provide an extremely low coefficient of friction, which provides added protection during high engine temperatures and other extreme conditions.
2) Thermal Barrier Coating (TBC) is a ceramic based coating applied to the crown of the piston that insulates the piston and rings against damaging heat transfer, keeping more of the heat inside the combustion chamber. It also provides a more even distribution of combustion, which not only increases efficiency and power, it eliminates hot spots that can lead to pre-ignition and detonation
3) Oil Shedding Coating is applied to the underside of the piston allowing oil that is splashed onto the piston to shed rapidly. The longer oil clings to a hot surface the hotter the oil and the part becomes. By shedding the oil more quickly, this helps eliminate hot oil from blocking the cooler oil from contacting the hot surface. cooler oil will be splashed over the surface more frequently.
The pistons are media cleaned first to assure a good bonding surface (ring grooves are covered). After the coatings are applied, the pistons are baked at specific temperatures and times.
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On the electrics, all I can say is just take your time getting to know the different circuits and understanding how they interact. After a while it becomes really simple, and almost meditative to work on. Just take it slow like you've done with the rest and you'll be fine. I started my project with about the same amount of knowledge and experience.