Contact Angola Canvas for the current prices. Below are the models that Angola has patterns for. The last number is the number of Sq yards of Sunbrella used--and determines the price.
The tabular format does not translate well to the forum.
C-Dory 6929A 25' Cruiser Full 2004 43.25
C-Dory 6929B 25' Cruiser Aft Curtain 2004 13.5
C-Dory 6927 19 Angler 2003 32.5
C-Dory 6574 22' Cruise 2001 36.75
C-Dory 7908 22 Angler 2001 37.25
C-Dory 6380 16 Angler 2000 22
C-Dory 6400 16' Cruise 2000 26.25
For example a C Dory 25 cover will use almost 2x that of a 16, thus the increased in amount of material and cost.
If possible try and get one of the UV resistant threads. They cost ten times as much as standard threads, but last years longer, with out the costly re-sewing of seams, due to UV degradation of the thread.
I have found Angola to be very responsive about the customization. I have also modified their covers myself, such as when I added Radar, and made a cutout for the dome, and then made a cover for the dome on top of the strut.
They will re-enforce areas where there are cleats or spots where chafing may occur.
For example Pacific Blue (the most common boat cover color) is $23 a running yard for 46" wide, and $27 a yard for the 60" wide. I usually go with the 60" wide for most marine projects.