Megastar Datasheet:"Short-time Overload 5 times of rated wattage for 5 seconds"
An 11W resistor that can handle a 55W overload for 5 seconds, can handle 110 joules of energy.
To not exceed the peak wattage, assuming a capacitor charged to 400V, from P=V2/R, R>=160000/55, which is 2.9K, and to stay within the 110 joule energy limit, from E=C*V2/2, C<110/80000, or 1375uF.
Assuming 100uF of reservoir capacitance, charged to 400V, its time constant with 2.7K will be 0.27 seconds, and after six time constants (1.62 seconds), it will be under a volt, so counting to ten will give it plenty of discharge time.
At the more usual 340V, there'll be a 38% safety margin on the power ratings, so there is little chance of the resistor failing.
The peak current will be slightly under 150mA (from 400V), so there is no pressing need for safety glasses, though, assuming you have a pair with optical quality lenses that wont increase your risk by distorting your vision, they should still be worn, in case you discharge to a point that isn't directly across the capacitor and maybe explode some other component.
I've discharged plenty of such capacitors with a suitable rectangular ceramic body radial leaded resistor held directly in my bare hand - if you hold it by the sides, even if the infill cement is cracked, the risk is minimal, but it might be more prudent to tape it to a tongue depressor or other short heat reistant insulating handle.