Bass strings online
I am restringing my 5 strings from B-E to E-C as I am having a 5 string upright built set up that way and I have been getting familiar with that set up. But, to try and get 5 string sets E-C is ridiculous, not sure why no one has stepped up to creating that set (to my knowledge). So, you get stuck with either buying a 4 string set and a one off C string or a 6 string set and trashing the low B. Anyway, https://www.bassstringsonline.com
was very helpful with putting together matching sets for me. I was focused on my ABG and so I got two different sets to try, TI acousiticores and Labella white nylon. I can recommend this site from a customer service standpoint, I do not have the strings yet but the guy (forgot to get his name) was really, really knowledgeable and helpful.