I did not have that file installed. h3dmode 5 ran as expected, but after reboot, my monitor resolution still reports as 1280x720.
A note here, I am using the display app from XFCE settings menu.
I installed the file then ran
and
Another note, the screen resolution would be fine except that it extends beyond the sides and top/bottom of monitor. If I recall, I had to set overscan on my raspberry v1 running Raspbian, but I see no way to do that with Slackwarearm.

deleted

something is wrong
1. installpkg sunxi-tools-git_20171207_5c19710-arm-1mara.txz

in /boot should be:
2. then set the desired resolution:
or
additional information on resolution

Yes. In /boot I have

analyze
if
screen0_output_mode = 5
ok

maybe you need another resolution, for example

I ran the analysis, and apparently h3dmode is indeed working as results come back showing whatever I set. And default resolution changes if I make large enough change. However, regardless of setting I choose, the screen still exceeds the edges of my monitor. h3dmode 5 still seems the best trade off as I can use it this way.

I have to pack it in for now. I have some other things I have to take care of before the day ends. I appreciate all your help, and especially patience in working with me. I'll return to this later in the evening, or tomorrow.

While out taking care of other business, I finally pulled my head out of my fourth point of contact and remembered I'm supposed to be a broadcast engineer (retired). When I did that I remembered 720p IS 1280x720. So the monitor is showing exactly what it should with those settings. I guess what was throwing me off was the fact that the default setting is all it allows.

use
without parameters will give all modes

Ok, I did something incredibly stupid even for me. The system will no longer boot at all so I am in the process of re-installing from scratch I'll get back once I have it back to the point I was at.

Been there, done that. I actually did buy the t-shirt too!

The number of times I've messed up my Slackware ARM system through testing cannot be numbered easily. So, you're not alone and it's nothing to be ashamed of. :hattip:

I'm marking this thread solved as it did do what I initially wanted. I'm moving to a new test with this device and will be starting a new thread. (or joining an existing thread)