No, except to say that you really have to flush it several times to get every last bit of the flushing agent, together with dislodged ferrous / ferric (iron) sediment out of the system. Invariably, this takes a fair bit of time, as you have to rough bleed the rads (to fill them back up with water) and briefly run the pump (to mix unflushed solution and fresh water up) between each drain down.
The number of times you do it really depends on the design of your system - some leave more litres of undrained sediment in than others.
Personally I do this in September - not in the middle of the heating system, just in case something untoward goes wrong, but it depends if you have a current problem, I guess.