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To get a high-wattage resistance, there are a couple of options: Get a bigger resistor; or make it out of a series or parallel combination of lower power resistors.

Tek chose a series combination, and chose not to implement that combination in the pcb artwork, but did show it in the schematic as a series combination. To me, that suggests a very deliberate choice not done in haste. The voltages are too low for flashover concerns to have been the reason here. I think that something else besides that or a parts shortage drove the decision.

To first order, the shunt capacitance in pF of a resistor equals the power rating in watts. A 1W resistor, or two half-watt resistors in parallel, has about 1pF in parasitic capacitance. But a series combination creates a 1W resistor with only 0.25pF capacitance. That's a consideration in a high-swing, high slew-rate blanking circuit, where you can easily burn ~10mA driving each pF of parasitic load cap.

To reap the full benefits of the series connection, you would want to float the common point above the pcb, which is exactly what they did.

I regularly use this method in rf circuits. The trade off is an increase in series inductance, but in this circuit, we're looking at 15 kilohms, so parasitic inductance is a non-issue.

-- Cheers,
Tom

Sent from an iThing, so please pardon the typos and brevity