When operating Category A, there should not be a need to top the engine as the flyways are designed to work within the engine power limits. They are what determines the weight.
As I said, I am not S61 qualified, but I have not yet flown an acft that Category A operations are requiring the rotor droop - all the twins I have flown predicate the Category A weights on 2.5 min OEI engine power, so it is good to learn about the s61 technique crab describes.
Drooping the RRPM on those twins that I have flown is generally a result of either a mishandling of the procedure, OR operating above Category A weights for the given situation (weight, power, p.a., temp, humidity, wind, HLS size, etc).
Category A requires a reasonable pilot to do the operations safely, and the reasonable pilot has a 2 second reaction to lower the collective. This will mean a bit of droop for the reasonable pilot which will ensure that the rotor is becoming more efficient (initially) and the engine is beginning to give you all it has. But if you then fly the published procedure, you should be assured of a safe landing/flyaway without any significant droop - if you are operating within the Cat A weights.
I think what is being talked about above is the situation where you are operating above Cat A and have an OEI event. How far do you pull?
The answer for me has always been
Pull to the 2.5 min limit.
If that is not working, pull to the bleed, maintain just on the bleed
If that is not working, maintain just on the bleed (say 95 to 100) to ensure max engine power and max rotor efficiency until you have to save the acft, then cushion on with what ever you want to pull to save the acft.
But none of that should be necessary with Category A which is what the thread is titled. No twins I have flown bleed for Category A, all do for weights above.