Help! My son is 6'3+ and very skinny, about 170. The size guide for this jacket wants me to believe that anyone from 5'10 to 6'6 can wear a large/extra large. I don't understand how an 8 inch delta in height can be adequately accomodated in sleeve and torso length of this jacket? Additionally, my son wears a medium based on chest (38) and waist (33) measurements, so moving to a large with a 45" (according to the size guide) chest - seems like he would be swimming in it, and that would somewhat defeat the purpose of wearing it....
Have any of you taller guys tried this jacket, and how did it fit?

Thank you.

Tech Specs:

Material:

[shell], DWR Coated UpCycle (86% polyester, 14% elastane); [dress], DriClime, UpCycle (100% polyester) 

Fit:

athletic 

Venting:

no 

Pockets:

2 front 

Hood:

no 

Weight:

12 oz 

Recommended Use:

trail running, cross country skiing, cycling, everyday 

Manufacturer Warranty:

lifetime