TonyV
What DNA Painter provides are very useful tools.
Firstly the Shared cM Tool is easy to use simply enter the cM value of your DNA Match and it displays the Percentage Probabilities of the possible relationships.
Ie enter 800 cM and it will display many possibles including 1C, enter 90 cM and amongst the possibles is 3C. So these results can help you research the xGGP level where the shared and you have the same xGreatGrandparent(s).
OK so I have a 364cM match but they have no tree and they have not responded to messages so how do I try to break down the brick walls.
I look at the shared matches between us and find one with a tree. I then start my own version of their tree and build it back as far as about 1841, then I look at other shared matches and build them into the tree, then the next shared match then I find how the 364 cM match fits in the tree and then I assign them as the home person.
So now I have a tree with some of my DNA matches linked together in one tree which I then create a Gedcom file for.
The Gedcom file is then uploaded to the WATO tool and for each of the DNA matches in the tree I put their cM value in their record.
Then I enter my birth date and answer the question by entering, where do I fit in the tree.
WATO then gives a whole series of hypothesis that may be possible and to each it give a numerical figure, the higher the figure the more probable the hypothesis.
WATO does have limitations which can be easily seen in hypothesis that are widely inappropriate.
Hope this helps.