If you have 26 skeins @ 109 yds...totaling 2,834 yds...you will have more than enough yarn for up to the size 48" for sure. The larger sizes require 2,928-3,660 yds...or so sayeth the pattern directions.
I made the size 46"...but my CPH took way way less yarn than the pattern stated. I dunno why. I used 12 skeins of Debbie Bliss Luxury Donegal Tweed. Total of 1,152 yds. Yet the pattern said I would need 1,647 for the size 44". It is still a mystery to me. Even IF I miscounted and had actually used 13 skeins, that is still much less yardage than the pattern said I'd need.
BTW: the pattern gives sizes 44" then 48". I made the 46" this way: I cast on (and followed directions for the 44") but used a slightly larger gauge using the US9 needle. My gauge swatch was 4 1/8" for the 17st in width. This 1/8" increased width per 17st rendered a size 46" garment.
The 48" was way too big...the 44" was a bit too small.
I didn't want a "jacket" that couldn't be worn with a shirt underneathe!