Congratulations Nick! The BL4s is a boss camera. I own two.
If you're on a budget, Zeiss CP series are nice. CP meaning compact primes. If you're really into saving money...the Meike lens are surprisingly good for the price. Duclos sells these, and I don't think they'd carry them if they were junk. They only have two focal lengths in PL mount thus far. Since you're shooting on film, it's okay to get newer lenses.