Setting up - Dialing in 3D printer

PRINTER: Maker Select Plus 3D Printer (Approximately 8 hours run time)
SOFTWARE/SLITTER: PrusaSlicer 2.5.0

This printer is probably 3 years old, I purchased it new in the box, tools never unwrapped or assembled, the factory test butterfly still on the build platform.

I initially ran it with the version of Cura it came with, however having a lot of stringing.

Found the YouTube user named Grimm, he had the same machine and was running the PrusaSlicer, and since I’m a total newbie I asked him for his configuration of PS, he went further than that and posted a video as to all the special configurations and after correcting a spelling error on my part it worked with my machine perfectly.

Now I want to dial it in and optimize the settings.

I didn’t know what testing to start with so I picked a couple in the photo below.
The Top back side of the cube is a little concaved, however the bottom of the cube on that side is very straight. The Y side has some ghost imaging to the right.
Any comments or suggestions for these conditions?

I also ran a Briging test, the large wheel type print. There is some fine stringing, but I really don’t know what this is really testing. Could someone comment on this test.

Could someone suggest what tests I should be running to optimize this machine?
Thanks
HH
Unable to post photo so I’ll post this and reopen and try posting a photo later.

Here’s the photo.

Gosh, you have bitten off a lot. New to 3D printing and new build it yourself machine.

In my experience:
You should print out a Benchy and post up some high resolution photos of the results. You will get your best response that way.
Also, ghosting is usually a symptom of poor rigidity. Make sure your belts are tight and it will reduce the ringing in the mechanics that causes the ghost image.
Start by testing the mechanical things first. Straight lines, extrusion temperatures, bed adhesion, testing should come before stuff like pressure advance and retraction distance.

Just my $.02

Tuning out stringing is mainly from two settings. Retraction and nozzle temp. With direct drive extruders 1mm is a good starting point. Temp is filament dependant. Most PLA's can be printed around 200 and petg around 240. Start with a stringing tower test. Thingiverse is a good place to find calibration models. Something like https://www.thingiverse.com/thing:2080224 will do. PLA for example, start the stringing test like any other print, then change the nozzle temp manually at given intervals. Look at https://www.thingiverse.com/thing:3477606 if you want the model to indicate when you change temps.

What are your general print settings? Speeds? Walls, top and bottom thicknesses? Cooling?