Leftovers are something that should be completely ignored in almost all situations. It provides little to no *actual* increase in bulk - 6% of the average life being ~22 = 22(.06) = 1.32 truncates to 1. In order to get a Leftovers recovery of 2hp/turn you'd need to have 34+ life, a number which Wailmer, who has the largest Base life stat in LC, does not reach. (I was off in this because Leftovers and other recovery is not truncated, it is rounded to the closest whole number. Regardless 2 HP is still very low and Munchlax and wailmer are the only two mons off the top my head to even reach that much recovery). In every situation Eviolite is a better defensive item as it will provide significantly more than 1-3 extra HP to your mon. Oran berry is significantly better because 10hp (with ~22 being the average life in LC) is roughly Half of a mons health - coincidentally, when it triggers. In this case, on Purrloin I still have to say not running eviolite is dumb. With full investment, you're reaching 13/14 in defensive stats. With an eviolite your defenses reach an "acceptable" 19/21. Those are VERY low values on a *dark* type mon. Which brings me to my next point: it's typing prevents it from even pretending like it could be a viable sub stall. Fighting is a very common attack type, which purrloin is weak too and quite honestly can do nothing to in return (Murkrow has SE Flying to scare off fighters, for example). Dark's resists include itself, ghost and immunity to psychic. Going down the list: A resistance to sucker punch is decent, but with at most 21 def, it will still hurt assuming its coming off a half way offensive mon. A resistance to ghost might net you a switch in on Misdreavus, who almost always runs a super effective HP Fighting along side her STAB for perfect coverage, and the immunity to Psychic might let you switch into an Abra. A neutrality or weakness to literally every other type, and terrible defensive stats and just barely subpar attacking stats neutor any chance Purrloin has of being a viable mon - even with a monster of an ability such as Prankster. Other dark types like Murkrow and even Pawniard make up for their Dark typing with a secondary typing and/or Absurd stats. Pawniard has one of the highest attacks in the whole meta, while murkrow can easily hit 18 attack while still netting the covetted 19 speed teir.
The point I'm getting at, and i dont mean to be harsh, is that you can tweak that set all you want and the only thing it will do is maybe make a hippopotas switch back in after drilbur OHKO's it outside of sand. Or it might make a Scarf snover miss a blizzard. Priority weather changing is powerful, especially when sand is as scary as it is, but this is not the way to go about it. I don't like making posts like this cause I know it stifles the creativity of our playerbase which is the #1 opposite way to go about getting a more posting forum, but I strongly believe we as a teir should stop trying to make obviously bad mons decent. That set can literally be slapped onto Murkrow like iss said (murkrow gets Raindance, unsure of sunny day). Cottonnee can do a decent sub seed set if you really want Sun for some reason. Would it work? I honestly don't know, but i can say it has a much stronger chance of working because the mon it's on isn't utter garbage to begin with. Like I said. I know this posts a little harsh, but I'm not going after any individual, its just purrloin is not worth our time.
edit: since this was necrobumped, I'm just commenting on a few things on this page of posts:
HP Psychic mienfoo would run HP Psychic for the same reason HP Ice mienfoo ran HP Ice: It lures and kills a counter. I don't think croagunk is as popular as it once was and I honestly wouldn't run that set unless i was counter teaming. It lets you run HJK on a scraggy, for example, using that mienfoo to lure in croagunk and KOing it. I'm assuming HP psychic OHKOs or at least does a sizable chunk - I feel the sets a bit outdated so I really don't care as much as to check.
Choice Band Axew: A possible over X-scissor would be Reversal. It might sound stupid to have a 2dragon/2steel attack set, but to my knowledge thats unresisted in the LC teir, all of Axews Coverage options are out-powered by Outrage, and Reversal would give you a very powerful move when low on health. Maybe not the most reliable thing ever, but its better than coverage for the sake of coverage, imo.
CS murkrow: I actually really like this if only for the huge power it provides at still very fast speeds. My only concern with it is my concern with all choice scarfers w/o utrun/voltswitch - its very easy to give up momentum when you're playing poorly. Its the main reason i try and avoid running them when i can in LC.