BillC

It looks like it may be the same switch used in the 1050, the following link is for a similar switch. I can't confirm it's compatible without measuring the footprint on the 800 power board, but even if it isn't there's likely another that is. https://www.digikey.com/product-detail/en/e-switch/300SP3J1BLKM6QE/EG5794-ND/1803781

I watched part 1 of your Incognito install video, the video shows making the connections to the CPU board but doesn't mention there is another CPU PCB version which affects where to make these solder connections.

This post indicates incorrect fonts were mentioned in the above post, and what the fonts should:

There is a hi-res image(2046 x 1971px) attached to the following post, information about the fonts in the post.

The keyboard of the 1200XL and XEGS include the 4051 multiplexer chip circuitry, a 1200XL keyboard won't just plugin to a 600XL. The simplest method would probably be to remove the 4051 chips from the 600XL PCB and connect the keyboard there, plus some other connections not routed through the 4051 chips. The other issue is there is no opening for the 600XL cartridge port, if use of cartridges is desired a hole would have to be made in the top of the case. IMO this makes the 130XE PCB as the better choice for a conversion, as was done by MEtalGuy66, since all case adaptations would be on the rear or right side where they would be less visible.

There should still be enough room in the case to add those features to a 1200XL PCB. FJC has added external PBI to a 1200XL.

The link in the post still brings up a price list. You can try contacting slor via PM, according to his profile he last logged in on May 20, or the mirrored email address on the price list. All Atari 8-bit computers are on the list, as well as all Atari made FDD and also several third-party models. slors collection is supposed to have served as models for the covers.

Slor sells custom dust covers made by his wife, available in cloth and vinyl.

FJC mentioned in post# 29 that 4-180kb ATRs would almost fill the available RAM, so approximately 720kb maximum.

A DD modified 1050 will only be able to access side 1 of a an XF551 formatted DSDD disk, not side 2.

An alternative with a similar color scheme is the Wico Boss Joystick, a fair number of which are currently available on eBay. https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=wico+boss+joystick&_sacat=0&LH_TitleDesc=0&_osacat=0&_odkw=xegs+joystick

XINIT.COM is the format utility for SpartaDOS 2.X/3.X, it will prompt you for needed information. The manual is available from Atarimania: http://www.atarimania.com/documents/atari-8bit-spartados-construction-set-owners-manual.pdf

If you have a PC with a 5-1/4" drive it may be possible to create ATRs of these floppies, then access them via emulator.

Also a useful method for upgrading to latest(Rev.C IIRC) firmware.

The chip selects on ROM chips can be customized, perhaps Atari ordered the 810 ROMs with CS1 and CS2 active high but didn't show this on the schematic.