There is no SOP more importand as common sense/airmanship.
The 1000' and 500' gates are proven gates to be stable by in order to maintain safety.
If I fly on final and see I tend to become too close to the preceeding I will slow down a bit, within 10 knots no problem, if I need more I ask ATC.
Before I slow down from 160 kts. I'll check what is behind me and how close, if it apears the A/C behind is a bit close...again Advice ATC.
This is indeed an interesting discussion here but it seems that too many are hiding behind SOP's but as an old instructor once told me:
SOP's are be followed blindly by fools or to guide the proffesional, you chose which is applicable for you.
gruB, Der Johny