Mm – you really only need to know which battles give the least points, and leave those on the map (in terms of scoring optimum points). By that stage, you’ll never have a choice between Arach and Matron, only the low-scoring Night Spider/Deep Huntsman and something better.
E.g., here you would just pick whichever battle isn’t a War Sphinx (unless of course they all are), and so you’re basically just rotating out one slot:
I actually tend to adopt a similar approach to Starlite, at least as long as I don’t think it will make my guild worry that I’ve gone crazy 
:
By taking all of the easiest battles earlier on, you can end up with a full map of lower level Mythic battles (which should supposedly be harder, but more importantly level up a lot more quickly).
Then, as you approach the end of your Sigils or your Guild approaches the last reward, you can switch to always avoiding the lowest-scoring battle.
This kind of min-maxing really only makes a difference if you think you’ll have trouble beating the higher-level battles, though, which isn’t really the case for a lot of forum players (but might be for their lower-levelled guildies). It’s also only temporary/limited to the 4 battles you can store on the map, so at most lets you play a battle 4 level progressions lower than you would otherwise.
I really only do it at the start, now, because it can be kind of fun one-shotting 5-6 Mythic battles in a row and I don’t want confuse people.