I find this type of approach works quite well for me for events of up to 200km anyway.
Its an approach that's probably evolved over many years. Part of it is that most folk who ride Scottish audaxes will both (a) ride faster than I find comfortable and (b) spend longer in controls compared to me. Im also very happy riding on my own as well, I don't feel that the enjoyment of an event is compromised in any way by riding solo.
Im not fussed about times, but then i know that in most normal conditions Im going to be somewhere around the 10 hr mark, and very rarely more. However on winter events I do like to minimise the amount of time spent riding in the dark, which Im not a fan of.
The only thing that I do on calendar 200s (that works well for me and it surprises me how few times I see others doing the same) is to have a big feed immediately before the start of an event. I've sat in the car outside the Focus centre shovelling in home made waffles like my life depends on it a few times. It maybe makes for a slower start but it allows me to do around 100km comfortably before stopping, with maybe only a back pocket bar or banana consumed during that time.
A good feed around 100km is normally enough to sustain me to the finish of a 200, and I'll have another snack on the move around 150km or so.
Of course, calendar events don't have the controls at exactly the spot to match hunger so some compromise is required, and of course there is the etiquette of supporting commercial premises by actually buying something to be considered too.
On events that are longer than 200km, I find that the need to eat is more frequent after about 200km and that while I can still follow the above up to 200km mark I'll be stopping for something substantial to eat every 50km or so after the 200km mark (and that its the rest as much as the food that is necessary)