Remington 700 sps varmint .308 longrange reloading

[past]

Hello

I'm a new user of R700 and .308 calliber. I would reload good ammo for 300,600 and 800 meters.
I have some expierence in .303 brit reloading
I'm from Poland and we do not have many powders and bullets but; Now I have Hodgon Varget and IMR 6064.
I would use Sierra MK 155 and 167 bullets.
Would you send me any your expierence directly with this rifle? I found some information here
.308 Winchester Cartridge Guide
I think about:
155 SMK ang Varget - 45,5
or
168 SMK and IMR 4064 - 43,5

My friends using VihtaVuori powder and Lapua bullets

Thanks
Pawel