Keep in mind that you're not going to get a t-handle on the thing. You're just looking for enough clearance to slip the spark plug socket into the hole and then place a ratchet, or a small extension and then a ratchet on the socket. It doesn't take that much clearance.
ANd some of us just decided a long time ago that it's just far easier to remove the rad, rather than fighting with it. It's easier, just as quick, the way to go especially if you combine it with a valve check at the same time.
I had to change mine in the parking lot of the local bike shop. And i took the hoses off the rad and had anti-frz all over the place. I was sitting in it and it took me like an hour and a half just for the front plug. It wasent fun. And after all that bull i found out that the plugs werent even the problem. I just had a little water in the gas so I did all that for nothing
You only need to remove the horn and bracket and then the three Radiator bolts. You can then access the front plug so long as you have the hinged Spark plug spanner/wrench from the SV toolkit(Using a 14mm Spanner/wrench on it helps) or a slim fit Spark plug tube.
The piece of card on the Rad is a Temp protector for the Rad fins and my knuckles. Also it's a good time to check the Spark plug cap as per,