One of these is homemade from a local shop, only available in this one ratio, but the other one is from a larger brand, I will check.
About the one that's homemade at a local shop...maybe a short, honest, conversation with the shop owner would have good results, for both of you. Most shop owners
want people to be repeat customers.
I'd start off with a compliment...by telling him/her that you
liked their eliquid and that you're interested in possibly regularly buying it. Then explain about your PG sensitivity, and that the 50/50 ratio is bothersome when you vape it. Ask if it's possible to have what
you buy made at maybe a 70VG/30PG ratio (or at whatever ratio
you know doesn't cause you problems). Maybe you could even say you'd call them a day or so before you wanted to buy it, so they can have it ready ahead of time. (Some shops here don't do custom eliquids simply because they don't always have the time nor enough employees each day, to custom make eliquids while also waiting on customers.) He/she just might be agreeable to do it, if it means they'd have a happy, repeat customer.
Just a little info for you here - It doesn't take any longer to make eliquid at 1 ratio or any other, nor is it any more difficult for the maker to do it. There's no real cost difference for the ingredients to do it, either. IMO, they may just have all 50/50 eliquids because of what I mentioned above, about time and manpower.