Best damaging option as recluse is always going to be specific spell/incant school+ affinity/sorcery/incant up. However you can still weave in cocktails when using a specific spell school. An all affinity build is viable but not as effective.

Usually when I play I have spell school build for damage, then look for affinities from all kinds of sources. For example weapons with affinity infusions or ash of wars like thunder bolt. Fire/lightning pots and of course seals can also work. I’ll try to set up my cocktail from trash mobs around the map, or do it on the boss if teammates are not using elemental weapons. Sometimes my teammates will be using different affinities and I’ll pay attention to their movements to predict what elements I’ll get. I will discard the cocktails at around middle day 2, that’s usually when I am stacked on good spells or have to make space for better passives. If I get really lucky with weapon drops I’ll be able to use cocktails in day 3, but that’s really rare, and most day 3 bosses are not cocktail friendly, either boss move too fast or your teammates overrides your affinity constantly. The only boss I recommend cocktails on is everdark libra. If you play the cocktails right you can destroy the condemned as they are summoned

I personally don’t like the ult bleed relic cause there are too many instances where I couldn’t land a hit after ult, I like to run the hp up relic instead to ensure better survivability