Hullo Peter & H; thank you for your response.
This is a brand new K3 Winner machine (or was last July), helpfully unpacked by Felder in my shop. "No calibration required".
I cut 2" ash, 1" hard maple, 3/4" plywood with consistent results- all bowed cuts.
I test cut a 6' sheet of 3/4" MDF and flipped the offcut over: the clamp in the first picture is not tight, it's just holding the gap closed.
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Daniel Day
Kitchener, Ontario, Canada