Not all female hogs are smaller than male ones, so it is not a very reliable way to tell them apart. I usually find behaviours are an easier way, but don’t normally rely on only seeing it once with a particular hog, but over a period of time, it becomes pretty obvious who is male and who female.
You will find that there are various ‘grades’ of aggression. Some will just roll up straight away, some will sort of lie on their sides and resist being pushed along with their feet and then sometimes give in and roll up anyway and some will actually fight back. It is not always the biggest hog who ‘wins’. The ‘fighting back’ seems less common here – they mostly seem to know their place in the hierarchy. Worryingly, the full on fights I have seen have involved at least one excessively artificially marked hog. As hedgehogs rely so much on their sense of smell it is possible that putting any artificial substance on them could be affecting their behaviour.
Re. the hoglets. The ones I have had here, appeared a month earlier than any last year. I saw the first one on 7th July and by that time they were independent. They are still noticeably small enough to be easily identifiable as hoglets. I haven’t seen any more new ones recently, but it is still early.
I usually transfer any reasonable hog videos onto a flash drive each day – it gets a bit out of hand if I leave it too long! So, the camera memory card gets emptied most days. I probably should format that more often then maybe, as you say, it would work better. I am now being a bit more careful about making a back up!