Choosing boots

Im looking to get mountaineering boots after a long time of renting and am stuck. im planning to climb a couple 6000m peaks next year in Asia , but also do quite a bit of mixed up to M6/7 (and hopefully some ice) i dont rlly want to buy two boots and have seen some guy on gear junkie climb w phantom 6000s on m7 aswell. my main concern is even if i wear a much lighter sock will a G2 evo or phantom 6000 be too much for 0C to -10C (14f), and how much does it hinder climbing (dont worry about weight as i am well used to climbing im Mont blanc pros/nepals which are a touch lighter)

Should i also consider a phantom tech or g-summit?

can i also push these boots past 7000 or should i just get a 1/1.5boot and use a 8k boot on the 6000ers

Thx guys 

Not sure what 6000ers you're looking to send in Asia, but I used my summer boots (think old Charmoz or Ribelle equivalent for Scarpa) up to 6000m with no issues during the summer in the Himalaya. If you're going fall/spring, going up to 6900m, or doing routes with bivys, then that's gonna be double boots for sure, just for the ability to dry out and stay warm if a storm comes in.