50mm is way too much. That should be more than half the width of the readable surface
As for "limited", every underfunded release is labeled this way today. It probably means as much as "180 grams" these days
Their price has nothing to do with quality, and all to do with small production quantities.
I cannot remember any off-center records on my racks, but I have many that are wavy
Sources: Modified SL1200 MK2, Salas folded RIAA, Phonoclone, VSPS, Shelter 501 MK2, Modified Pioneer P6D6 as transport, Shigaclone transport, Peter Daniel NOS DAC.
Amplification: Custom 211 Monoblocks, Electrocompaniet AW120, Audio Research VS110, Gainclone
Loudspeakers: Tannoy Turnberry, PBN Montana EP Signature
Cables/stands: Tempflex ribbon and Twinax cables
Other: Promitheus Signature Passive Attenuator, Custom JFET - transformer preamp.