If it helps, I wear my K25 sellier (and B25 sellier as well for that matter) very casually.Please help me with my 2025 wishlist! My SA has asked me but I havent decided yet!
what I have: gold B25 togo, mushroom K25 togo, Etoupe Kelly Pochette, black constance mini
what I don't like: B30 and K28 - had them before but sold them
I once asked for MK2 but my SA told me it's extremely hard to get. I think she meant my pre spend is too low, but I dont want to spend a lot just to get a bag, so I guess i can pass MK2
Now I'm debating on what I should put on my next QB...personally I prefer Kelly over Birkin since Kelly has a strap, but I dont know if i need another K25 togo....also I feel like K25 in Epsom is a little bit formal, not casual enough

But I agree with @HappySteve above - just ask for the MK! Worst case is a no for now, but at least it'll be on your SA's mind. If you really want a MK but settle for a K25 or B25... you'll likely still end up wanting the MK and have to spend even more money to get one. XD