So now your talking about the surge, this is well known with de-catted headers, mine was awful pre-flash and is now far better, still does it a little, but I can hold 30mph in 3rd or 4th now, I now only get this when trying to hold a steady 18-19mph in second - again IMO it is easy to ride around, but I have had around 150,000 miles on motorcycles, so you will probably get the hang of these throttles and gears over the next 30k
But earlier you were actually implying you could not control the bike...
Well in my 150k miles I have found holding on is a good idea, especially when accelerating quickly, in my case this knowledge is backed up by a GCSE in Physics which confirms when accelerating the laws of Newton come into affect and without holding on you will indeed fall off.
You also mention the pull at full throttle in 2nd concerning you - well try 3rd (again after 150k miles I have discovered that the gear ratios overlap enough for you to be able to use more than one gear at a particular speed) or use a bit less throttle, the throttle is a linear device connected to a potentiometer (something I learned about whilst an apprentice electronics engineer, and with over fifteen years working on electronic equipment I can clarify these definitely have multiple settings) this will reduce the amount of acceleration and decrease the amount of holding on required - it will also reduce the flashing of the TC light which also seems of great concern.
I hope this helps