I mean I eat very close to the same thing every day, so I am perhaps not the best example, but for example:

> - sauces you make yourself? I often mix some different oils, mustard, seeds, miso, bit of leamon juice and spices… but weighting and logging everything will take 3x the time to do the sauce itself

You weigh all this out once, store it as a recipe and just weigh how much sauce you're putting on things. Oils are so high calorie they're basically all the same, and the only other contributor is really if the seed mass is substantial. Log your upper end, and just assume the sauce comes out as that value. Your sauce recipe is hardly going to vary by an enormous amount, just provided you bias it towards the upper end for the purposes of tracking.

EDIT: Also since people have been dropping app links - https://github.com/davidhealey/waistline this is what I use on Android. Libre with nice integrations, works great.