The air box/frame runs over the top of the motor like an arch. Removing the fuel tank allows access to the inside of the air box but it does nothing at all for access to the top of the engine.
If you are doing the first valve clearance check, i might suggest removing the throttle bodies to open up more space. You would have to remove the fuel tank to remove throttle bodies. If it's just spark plugs, you don't have to take anything off but the stick coils and wires.
You do not need the heat blanket on the motor or the air box. You do not need the PAIR solenoid but would need block off plates if you take it out permanently. You can also remove the dirt shield / plastic heat shield wings at the top front of the motor. You can remove the LH frame rail but would need to rig up some fasteners for the wiring harness and clutch line. Take the horn and triple tree cover off while you're at it. All together, that's 5 lbs gone.
I have tutorials with pics on all of this. Let me know if you want me to reload pics.
'08 MIDNIGHT SAPPHIRE BLUE Now Deceased