My dear, you can get an excellent pre-loved BBK with GHW for $7K, maybe less, unless you need perfection (and honestly, if you want to use the bag, you don't want a perfect box calf bag. I have one, my Rouge H K, and I rarely carry it because it panics me - I have actually thought of buying a SECOND one that has marks on it, so I feel fine carrying it every day).
If you're budgeting around 30-35K for two bags, you can get the gold and black preloved and have all three. As someone with red, black, and gold Kellys, that's all you need IMO
although at some point you might get a blue or a purple
Etoupe to me always looks nice in photos and when I try it on I find it
I don't have my BBK 28 anymore (a wonderful tPFer has it, and I have my new black Togo K32 SO), but I have had box calf caught in the rain many times and as long as you wipe it off, nothing bad has happened so far. There is a conditioning technique you can use to waterproof box as well. Living in Florida your biggest issue for any expensive bag is humidity/mold when you store the bags, but as long as it's a dry room you will be fine
I did wear my BBK casually when I had it - the "how to wear a Kelly casually" thread is super helpful here. I find all my Kellys versatile that way, especially in 28.