Put your board together and go out to skate with it. Then come back and tell us what you think about it. Your opinion is the only thing that matters. The bigger the number the harder the wheel. 104a doesn't exist.
Shore hardness is measured using a device called a durometer.
The hardness value is determined by the amount of penetration by the durometer into the material being tested. In other words, it's impossible to have a reading higher than 100a. Wheel companies use numbers like 101a and 104a, but they aren't actual figures, just marketing hype. The Shore A scale is designed for measuring the hardness of rubber and softer plastics. If you're measuring something harder than 100A, you need to go to a different scale.