thanks for all the answers everyone!
so my plan right now is:
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4-core shielded cable per sensor, AWG20, shield grounded at MCU/hub.
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Bulk cap at hub (47–100 µF, 25–50 V electrolytic), across +5V–GND.
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0.1 µF ceramic + 10 µF electrolytic in parallel, close to the module pins, for decoupling at each HX711
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One shared CLK, buffered. SN74HCT244 placed at the hub, 33 Ω (or higher) series resistor at each buffer output (driver_pin → 33Ω → cable).
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Optionally lower clock rate (10 kHz)
and I will probably use a Teensy 4.1 as my MCU