You really need to run on the road to see the real temps and the front/rear difference. I suggest the purchase of a 2-channel thermocouple temp meter on ebay for ~$15.00 US which will come with 2 type K thermocouple junction probes. The junctions can be crimped into ring terminals and used under head bolts, or much better under the spark plugs.
I just returned from the first Cross Country Chase (themotorcyclechase.com) which ended in hot Key West, Florida. I rode a Danish Nimbus, which has a 750cc inline 4-cyl engine with all 4 cylinders in a single casting. The front & rear cylinders run cooler. The plugs are normally B6HS. I set the mixture much richer than normal to run cooler in the hot south, but this fouled plugs 1 & 4, so I changed just 1 & 4 to hotter B5HS. Now the plug tips all looked the same and the head temp was as much as 100 deg F cooler than before. After more than 2300 miles at ~50 MPH, the bike still runs fine and oil consumption is slightly reduced.