Hi K in Iowa!

I've learned a bit since the original post!

Like this.  We have been used to using Presenter view, where, on the laptop, the slide projected is on the left, and a smaller sized 'next slide' is on the right. If you have added notes, they are on the right also.

Now - herin lies the  problem.

If we do not use Presenter -  the slide on the computer is duplicated on the data screen.  full size on our new 16:9 ratio screen. [and no option to do things like 'blank screen' to allow people to concentrate on the speaker, not the screen!]

But if we DO use Presenter, the left hand slide is [as said] shown on data screen, BUT only 80% screen roughly on our new 16:9 screen. 

On my home desktop [Win 7] the P/Point gives me a choice of 'resolution' in the top bar when in Slide Show.  It goes from 800 * 600  to 1920 * 1080.

That option is not available on the Win 10 laptop that is connected to our data projector!!!

I might set up three P/P's using different resolutions -  and go try them through the church system.

On the Win 10 I did find an option to vary 'slide size'.  Had a bit of a tinker with that - but did not notice any visible difference   -Presenter still put the slide chosen up with a black border around it.

Asking Google for help, I find that 16:9 ration slide size is 10 inches by 5.625 inches  [ Metric equiv.  25.4cm by 14.287 cm]

Google also mentioned "Widescreen" dimensions 13.333 inches by 7.5 inches  [Metric 33.86 cm by 19.05cm] .

Both these are roughly 16:9 ratio according to my maths!

I'll give adjusting that setting a try, and see if I can fix my problem.

[At home , as I have no 'second screen', I cannot give it a trial run!!]  Edit :-  I can run Presenter using Alt F5 - but that just gives me the familiar 'screen shot + next shot' side by side format.

Frustrating  - to say the least!