WOW!
I stepped out for about one hour and I came back to this new Thread.
Everbody just fucken smashed it out of the park.
@Anti like the others mentioned, Well done on your research!
Honestly
It makes answering your many questions ( Not a bad thing) much less time consuming.
I think all your questions were answered, and some really great advice in there.
FYI with an ACR122U and some software you can also write to the xM1.
At the bottom of the xM1 product page is a video and some links.
FYI the xM1 will have 2 Flex versions out shortly ( No dates, DT are waiting on parts )
Biggest thing of note is the FlexM1 gen 2 will be able to be written to via an Android app
HERE is Amals blurb explaining the differences.
Placement wise.
Correct DO NOT place xM1 or FlexM1 near the NExT
always keep seperation of the same Frequencies
You will likely get in your product order, some of the essential accessories you mentioned
KBR1, Diagnostic Card, xField Detector(s), You will find these invaluable.
You will also get an xAC, which is a great product for project and your NExT - xEM
Heres my suggestion to you:- ( a bit of an $$ investment, but you don’t have to get it all at once
NExT ( accessories included in purchase )
Decide on what you want where, make sure you think ahead, future proof your self. Make a wish list of current and future devices ( Draw on your hands if you want( photoshop or physical ) and upload it, we can all give you some advice if anything looks out of place)
You will need to think about xSeries vs Flex, and find locations that suit and the biggest consideration, is make the ones you use the most, the most accessible.
When you are ready to write anything other than NDEF to your NExT - XNT with your phone,
Then grab a Proxmark Easy ( could go RDV4, but probably overkill at this stage )