If you ever get a chance to play with a 450 and the tuner, pull out the ignition advance between 1,400 rpm and 5,000 rpm, then taper it back to standard advance between 5,000 rpm and redline. (I have not used the yamaha tuner, only the honda one, I have been told the yammie one is easier to use, but not as sophisticated (you cannot go in as fine an increment of tune range as you can on the honda system) but the end result should be the same.
Do not mess with the 0 - 1,400 rpm range, that is your "starting block" if you play in that zone it may cause hard starting. Once you get the hang of using your tuner, you can start to fine tune this block as well.
For offload use, or just trying to "tame the beast" for nasty conditions:
(1) Use max retarding of ignition advance. You taper it down from standard advance, start taper the ignition advance down at 1,400 RPM get to max retarded setting the program will permit (the programmer shows the safe adjustment range),
(2) Maintain max retarded ignition advance till about 5,000 to 5,500 rpm
(3) They you can start to taper it back up again if you want a strong pull available say 3/4 to full throttle, otherwise, leave it as in step (2) above right to redline.
Then you can fine tune fuel settings to match, you can also restrict the air intake and use a quieter muffler. This combo will make a YZF or YZF450fx feel very much like a 350.
Once you get comfortable with how easy it is to make big changes, you will see just how versatile the new bikes really are. The programmable ignitions are a game changer, especially for converting 450cc fire breathers into fun enduro racers or trail bikes (or novice friendly mx bikes)