We see the letter from you,very shocked,for dusts in bars,it is normal reaction on stainless steel,you just need to remove it by any cleaners,as the dust is not from bars inside,but is reacted between bars outside and air and moistore etc.
Bending:after we are making annealing,we do straighting bars by machine,pls note.
Tolerance:we do as per h9 tolerance,but seems your request is super more than h9.
Lastly,we wish you can hold mutual business principle and settle all problems inside,as all are minor problems,we can take many methods to modify,not to say refund or re-make,which could not beneficial to we both.
And most importantly we kindly recommend you to test all bats in chemical and physical to see quality of our bars.