Family Historian User Group

The present state of my one-name Coldwell study is that my data consists of several unconnected large sized trees, some medium sized trees ... down to couples and unassociated individuals. Total 17,000 persons.
I hope to do more study to associate some if not all trees and for that reason all the data is contained in a single GEDCOM.

It appears that FH6 will only allow me to see one particular tree at any one time. Also in order to choose a particular tree I must know a specific individual in that tree. This makes it very difficult to try to find individuals who are the same person but in different trees possible with slightly different details and different amounts of information on their ancestors and descendants. It is difficult to link trees via that common individual unless more than one tree can be accessed at the same time.

Any suggestions on how to manage this issue would be appreciated.

Are you referring to viewing more than one diagram at a time?
In very the top right corner of the screen there are three buttons which minimise, maximise/restore-down, and close the entire FH window. Just below them are three more identical but slightly smaller buttons which do the same for the windows within FH. You will find that if you open two or more diagrams you can then click the 'Restore Down' button in the middle of this second row and multiple windows will be displayed at once. You can then resize and reposition them to see two at once.

In your search for matching individuals you might also find the Find Duplicate Individuals plugin useful. It has various parameters which can be used to allocate scores to potential matches.

To allow multiple Diagram Windows ensure Tools > Preferences > Navigation has Re-use Open Diagram Windows set to Never.

Another way to see two trees at the same time is to open first tree as normal, then use Diagram > Insert into Diagram and insert a second tree into same Diagram Window. The Moving/Resizing dialogue will open automatically, so you can drag the two trees around independently.

Despite its name you will find the View > Standard Queries > Search For Orphans useful to identify who belongs to which tree, because each tree is given a different Pool number. So everyone with the same Pool number are in the same family tree. Click on the Individual column heading to sort alphabetically, and all persons with similar surnames will tend to come together, and if they have different Pool numbers are in different trees. It would also be possible to include Soundex surnames and sort on them.

all persons with similar surnames will tend to come together

As JKC is doing a one-name study that may not help much.

True, but if they also have similar first names they might come together, although as you said Find Duplicate Individuals is a better bet.

I used the Search for Orphans query very successfully for just this purpose. It can get difficult to keep track of individuals who may well appear on several different trees. In my case the details had been entered by three different researchers over a 15 year period. The pool numbers were very useful in getting to grips with the fact that a significant number of individuals appeared on up to three trees of varying sizes.
Anne