Building a 26″ wheeled “fun” bike. The bits box has yeilded a 32t chainring and an 11-34t cassette. On experience is the cassette a little too big? Should i be looking at a narrower range? Bike will be mostly for mostly dh fun.

Be fine. I’ve now got an 11-36 on my DH fun bike!

32:24 is a good winching up gear. When you say mostly DH fun do you mean ride to the top again or DH hardtail.

a decent chain device will be more important

Personally I prefer a wide spread I find it makes things easier.