SP, thanks for the clarification. But still, the OP seems lacking if real information is desired.
In the jurisdictions where I have flown, a VFR quadrantal is not an even 1000', that would be an IFR altitude. The 500' offset up from that is the preferred (prescribed) altitude. I know, telling you what you already know, but stating it for the sake of the other readers. I do not know what the current European view on these things is.
My advice about SA was to address the implication that a poll like this could establish what a good deconfliction offset is.