I'm 5'11", maybe 6'1" with my feet stretched out. I'm concerned that getting the long bag will mean heating extra air (I'm not a warm sleeper), but I'm in love with the stretch feature on these bags. Is it worth losing the stretch feature for warmth, say, going with the Marmot Couloir?

Tech Specs:

Material:

[Shell] 15-D Ballistic Airlight Nylon 

Insulation:

800-Fill down 

Shape:

Mummy 

Draft Collar:

Yes 

Max User Height:

[Regular] 5ft 10in (174.8cm); [Long] 6ft 4in (193.1cm) 

Shoulder/knee Circumference:

[Regular] 53-71 / 43-57in (135-180 / 109-145cm); [Long] 57-76 / 47-63in (145-193 / 119-160cm) 

Stuff Size:

[Regular] 7.3 x 14.7in (18 x 37 cm) [Long] 7.4 x 14.7in (18.8 x 37.3 cm) 

Stuff or Storage Sack:

Stuff 

Degree:

0 (-18C) 

Weight:

[Regular] 2lb 13oz (1275.4g); [Long] 3lb 1oz (1389.1g) 

Recommended Use:

Mountaineering, winter camping, backpacking 

Manufacturer Warranty:

Lifetime 

Country of Origin:

United States