Board Thread:Fleet's Prepared-ness/@comment-29630844-20161010160240/@comment-26717891-20161011093014

37 and 38 are probably the best, if you want to focus on a specific resource.

they last only about 30 mins more than 21, but with 3 daihatsu and a full sparkle yield around 750 fuel / ammo, depending on which one you're doing, and around 400 steel each with a Great Success.

Also, you have a decent chance of getting Great success even without sparkling when you're doing them (around 20% I believe, but have no source apart from my own experience)

I prefer them over the classic 5-21, since they allow you enough time to sparkle other ships between runs.

But ultimately depends on your free time and tastes.(also they net quite a nice amount of steel)