The TS-Optics 90/600 APO Triplet uses metric screws. To fix the ZWO EAF standard adapter plate to the telescope I used

• 1x M4x10 screw + ring washer for the central slot (comes with the the ZWO EAF focuser)
• 2x M3x25 screws + ring washers for the left and right slots - the screws are available from a local hardware store

Original state of the focuser mounting plate:

Final assembly:

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