I'm confused.
I want to preface my remarks by stating that I have never even fired a 35 Whelen, much less loaded for one.
That out of the way, I understand the 35 Whelen is simply a .30-06 necked up to 35 caliber.
There is myriad data for 30-06 with 165gr bullets. Why can that not be used as a starting point ?
Or, failing that, perhaps using 9.3x62mm data as a start ?