What is the runout like at the muzzle? The hole itself might be centred at the muzzle end, where the ball leaves. If the hole is in the centre at the muzzle, it matters not if it is off centre at the breech - the ball will be started virtually straight with the barrel (if centerd at the muzzle) It is common for the drill to run centred after having a 'wonk' to it, or to gain a 'wonk' while it is running down the blank(offcentre in the middle lony), then run centered or to cross/over from one side to the other,ie: thinner on one flat, and thick on that flat at the other end which would actually be a straight hole with gradual incline (hopefully). I would put the thin flat down, so to theoretically make the gun shoot higher. It is an easy matter to file less of a front blade (when lowering point of impact) and to use a low rear sight, than to have to have a really high rear sight and barely more than the base for a front. It having the gun shoot low, would allow a barelycorn front sight, though- maybe.
The higher front sight allows 'holding sight' (above the rear flat) for longer shots. A low front sight doesn't allow this. Holding front sight 'proud' is easier, more precise than holding barrel above the flat of the rear sight. With a descent charge, the .32 shoots quite flat and very little 'sight' is needed for shooting 100 yards. With a 25 yard zero, it's zero'd at 50 and only about 4" to 4 1/2" low at 100.