D.S.,
You have a good long range set up idea but for game such as deer, I generally do not recommend the 6mm using match bullets.
This is not to say they will not perform and kill deer, its just that the small match bullets do not have the advantage of frontal area and weight like your 190 gr .308" bullets do.
Of the two bullets you list, for deer size game I would recommend the SMK as it has a heavier jacket then the Berger and will generally penetrate better on target.
I would personally not use any Berger on deer size game that was smaller then 7mm in caliber just because of their very thin jackets.
For varmint hunting at long to extreme range you may want to look at the 105 gr A-Max as it will offer much more reliable and much quicker expansion then the other two bullets you listed.
Accuracy wise, all three bullets have potential to hold well under 1 moa out to 1000 yards easily. The question is which bullet your rifle likes. Try them and see which is best.
When ranges get long the smaller 6mm rounds will loose effectiveness on deer size game. If your hunting smaller southern deer you will be much better off. IF your hunting large mid west deer or norther deer, I would not recommend the 6mm class rounds for use over 400 yards or so to be honest.
Not that they will not kill well, but these deer can get well over 300 lbs live weight. This is alot to ask of a 6mm round shooting a match bullet. Your 300 Win would be a much better choice for heavy norther deer.
Kirby Allen(50)