Allright - another update which means progress...I hope... The rear tank set-up is working great although I am still tweaking the filler hose set-up. Might eventually have to bend (well find someone with a bender) some thin wall tube and make a better filler. The hybrid rubber hose and 90 degree exhaust connector likes to get jostled around and is hard to keep a good seal with the hose clamp. Only drips a few drops when filling but its a work in progress... As for the good news...I think I have the tank switching mechanism all set-up (given the recent snow storm here in CO I haven't had a chance to go fill up the second tank to really test). I used an electrical 6 port mechanism that switches fuel lines (to carb and return) for each tank as well as switches the sending unit so the stock fuel gauge will read whichever tank is being used. This is the 'pollack' style 6 port switch- I think its pretty much the same switch used by all the FLAPS under different names. I got the full range of FLAPS all very close, but when I need some parts counter help, my friends at the carquest are truly helpful so I try to buy from them when possible. So, for them the switch is the BWD FSV3 (fuel switching valve 3) and associated FSV3a wiring plug. Total cost around $90. The only real frustrating part was I could not find any of these valves with 5/16 fuel line and 1/4 return - they all come with 3/8 and 5/16 respectively. So that required stepping the hose sizes down to fit. This pic shows my initial attempt...I ended up changing this a bit as the entire set-up was physically bigger than I was thinking and thus had to kind of squeeze it in. After changing the hose connectors around a bit and lots of test fitting as well as modifying the hard fuel lines I ran from the rear tank and mounting on the fire wall... I used a DPDT switch and wired it as found on a number of threads on this site...they definitely don't give much info about wiring the harness with the parts so I will see if I can add those to this post for future reference. Where to put the switch has been a big internal debate...for now I put the switch above the steering column because there was already a hole in the dash there that had a plastic cap covering it. I think I prefer having it over between the flasher and choke - there is also a capped hole there - but that hole was a bit too small for the switch and since I am not 100% sure where I want it, I don't want to drill any unnecessary holes in the dash. Also, I put the switch so that the down is for the rear tank and up is for the underseat 'forward' tank. That has also been a big internal discussion...the time spent thinking about the aesthetic and functionality for such little things!