My heritage-plant P. rothschildianum is still potted in the pot in which it arrived 3 years ago...I think it’s time to repot. Meant to this spring but, you know, COVID. Any recommendations on mix? Grade? Should I get a bag of Orchiata and if so, what should I add? Not a lot of experience with Orchiata but I like that it’s so durable. Window grower, Chicago, using RO/K-lite (mostly; some tap). It’s in a plastic nursery pot; I’d love something more attractive but for such a big plant. Thank you!