The running temp. between 16% and 20% should be negligable but I could be wrong. You don't want to adjust the HSN according to what fuel you are running you want to adjust by what temp the motor is running at. The factory setting on the high speed needle is 3 1/2 turns out start there. Adust the HSN in 1/8 at a time giving it a few minutes of running to get used to the new settings and check the temp. continue doing this until a temp of no more than 270 degrees is reached. Digital thermometer's are relatively inexpensive if your hobby store doesn't have one check you local electronics store.
The low speed needle sounds like it is to rich and needs to be leaned out at least a 1/4 turn. If is to rich it will take a while for the excess fuel to burn and return to normal idle and it will bog then accelerate. There should be no bogging when accelerating. If it speeds up then bogs it is to lean.
When you adjust the idle make sure your radio trim is at zero. You do not want to use the trim to adjust the idle speed.
Personally I can't tell the difference between 35 and 45 mph on a 10th scale truck and where I run it, it never really reaches top speed.
Alot of the tuning procedures are listed in the CEN nitro manual if you do not have one it can be downloaded from www.cenracing.com.

Hope this helps, rolland