From the imformation you have given so far, it seems you want a big caliber . Instead of the Dakota, I would go with the following:
300 RUM: 210gr Berger @ 3100+ (28" barrel)
300 JAZZ: 210gr Berger @ 3100+( 28" barrel)
240gr SMK @ 2900+(28" barrel)
338 EDGE: 300 SMK @ 2800+(30" barrel)
338 Norma Mag 300gr SMK @2750 (26" barrel)
@2800+(30" barrel)
The 300 JAZZ and 338 Norma Mag don't require an extended magbox to load the 210 Berger or 300gr SMK at the proper neck / shoulder junction.
The 300 RUM and 338 EDGE would.
All of these are great calibers and would make great longrange rifles, if you need the foot pounds of energy at distance to take big game.
If you don't need the foot pounds of energy at distance, and just want to shoot longrange, there are better calibers to learn on and enjoy.
I would recommend the 260 Rem or 6.5x47 Lapua. Both more than capable of 1000yd shooting.
As far as stocks go, I only own Manners and HS Precision.
Soon to have a show stopper from Joel Russo thou.
For your first custom build I would not go beyond these calibers to a 338 AM or Snipe-Tac. That is alot of gun, and something to be eased into.