Congrats on the "new to you" bikes. I kinda like the GS450's too. Not sure what I'd do, probably like others have already said I'd get the "T" model running first, and then goto work on the "E" model.
1997 Yamaha XJ600s Seca II - mostly stock, Oxford Heaterz heated grips, Barkbusters Blizzard Cold Weather Handguards, a Scottoiler auto-chain oiler system. My Mileage Tracker Page