I'm not convinced behind his reasoning for sharing the neutrals in his additional 120v sockets as well.. If the power factors of the loads are different then it is possible to exceed the rating of the cabling.
The proper way of doing this is therefore taking cables that are rated (much) higher than the fuse. Which makes a lot of sense and is even mandatory in most countries. The fuse should always and only be the limit, not anything else.
If you doing it well you also just standarize the fuses and wiring to a set value. (10, 16, 20 and 26A for example)
But I have seen many "safety codes" in some countries that are just simply dangerous.
For example, some countries don't work with a real earth/ground fuse/switch, but they only detect the imbalance of live and neutral. That is just asking for trouble. Not only is it possible to have accidentaly both shorted to ground (which means there is still nothing out of balans), it also doesn't care if there are any issies with the secundary side. Which can lead to very dangerous situations.
(I have even showed people these situations)