I would absolutely NOT do this.
Call the company and if they don't handle it, find a big name place that still sells it, buy it, put this one in the box and return it.
I've seen serpentine belts come off and take out AC and power steering hoses.
I can only imagine the carnage from the fan coming off too at 5000rpm while you are driving.
I'm also not sure of the shear strength of 10-32's or if they really make grade 8 versions. As an electrician we use them all the time and if you pull on them, they are strong, if you side load them they can be bent or broken.
This is a pointless gamble and you may spend the rest of the time you own the car wondering when the fan is going to fly off and if and when you forget, that's when it will happen.
I've broken a belt when driving, it's kinda scary for a moment as you really don't know what's going on, especially since the steering barely works.