- ReverseEMF......
I agree on a mosfet - a bit dearer, but a better choice - easier to drive, much lower 'on' resistance.
eg IRFL44N, FQP30N06L.
But a BC337 would do. Just about. And very cheap.
Zetex make some very good switching BJT's - eg the ZTX450 for this application..
Your analysis is more or less what I did.
Allan