I used google to search for "dmc and "rgb".
I found
I downloaded the spreadsheet from
Then I coerced the values into the thread.ini file which I provide.
I wrote a program to tell me which colors were similar to other colors.  It found several exact matches, such as 504&505, 407&3064 and 3849&3851.  When I bought each of those threads, they didn't look identical.  So I decided to scan all the threads and create my own palette.  Fortunately, A.C. Moore was having a sale, 12 cents per skein.  So, for about $45 I bought all the threads I didn't already have.  Next, I scanned all the threads, about ten at a time.

Then I cut out a 100x100 pixel sample of each thread.
Then I wrote a program to count the brighter than average pixels and compute an average of them.  This average was then stored in thread.ini.
If you view thread.ini, you'll see collections of lines such as:
desc="Very Light Dusty Rose"
This describes DMC color #151 as "Very Light Dusty Rose" with an RedGreenBlue value of 254,195,210.  The priority value ranges from zero to nine.  On the main window, there is a priority setting.  By default it is zero.  The priority setting indicates which threads to exclude from consideration.  If you set the priority setting to a number greater than zero, thread #151 won't be used.  Here's how I envision this feature being used; for each thread you already own, set the priority to one in thread.ini.  Then set the priority setting to one as well.  The program will now only use threads you own when making a pattern.