Very appealing bike. Wonder how it would look if you left the 24" on there and put a skinny 26 or a 700c on there 24 on the front?
Great ides about tunneling the tank. I've Got a new one I might try to do. Did your tank have gas in it before?
They've been known to explode from vapors cooked out of the metal when welded without extreme caution.
One old school saw done once was to fill the tank almost full with water before welding and weld where the air pocket is. Had to leave a way the pressure to get out
You can use chrome plastic door edging from AutoZone ect on the seam flange. Really looks good.