I don't do eyelashes on my Sims4 peeps because I don't model with Sims4, only Sims3, but sometimes CC lashes don't fit the eye shape properly. I used to be a huge fan before Sims4 came out of using eyelash brushes on my sims. This was before we had S-Club's eyelash mod for TS3. After S-Club came out with their eyelash mod I've really only used those and Sintiklia's if I want NUTSO lashes like lace pattern or feathers.
But that's all for Sims 3.
But heyyyy I think your eyelash placement looks pretty awesome! I'm not sure how I'd say to make them better cause I'm not sure what method you used to do them, but I think they look pretty spiffin'. They seem kinda Maxis-match-y. Whatever you did, you did it quite well.