Best way to assign chromosomes to certain ancestors?

[thecalifornialife]

So I got my mom and myself tested on 23andme. My mom has a 2nd great grandpa that was adopted. I basically just found out about him from a old letter from my great great grandma to my mom. So I’m trying to map the chromosomes of my other ancestors to eliminate certain cousins that I know aren’t related to him. I’m hoping to do this to find cousins who are related to my great great great grandpa and compare Ancestry trees. Does anyone have any suggestions on the best tool to do this?

[UK4753]

Check out DNA Painter.  It's free and should do what you need.

https://dnapainter.com/

If you can upload the 23andme files into GedMatch and then download into DNA Painter (plus any other strong matches), then you are home free.  But if you only have the locations of the matching chromosomes you can manually enter that information into DNA Painter.

Another option is to upload your data into MyHeritage.  They have a chromosome browser as well.

This all assumes that those hidden cousins have tested with Ancestry, 23andme, MyHeritage, etc.  If all you have is Ancestry matches then your task is a bit more challenging.