Hi Floyd!
Mandolin and bossa is a delightfully pleasing combination you’ve used. I reckon the mandolin is a much underused instrument outside of bluegrass, and yours is no exception. I love the interplay between the mandolin and and your lead guitar towards the end of the piece.

A song that has novel but critical use of a mandolin is Chris Cornell’s (ex Soundgarden) Nearly forgot my broken heart

A few years ago, I bought myself a Fender A-style mandolin with built in pickup - it’s action was set much higher than I could use and felt like fingering granite - so like you, I sanded back the base of the nut and lowered the bridge so get the action height I could play. But I digress.

Love this piece Floyd!
Andrew