HVAC AC Capacitor Replacement
1) Higher is better than lower--BUT you do not want to go too much higher. Given the relatively tight (and odd) 6% tolerance on the original, you would not want to exceed 58uF with the replacement cap. The ESR on the replacement cap should be very close to the spec of the original. (56uF is a std value, 55uF is not).

The following is a good reference: https://inspectapedia.com/electric/Motor_Capacitor_Selection.php

I have never seen a tolerance of +/- 6% before. 

However, the identical replacement cap you seek is available here for ~$26.

https://www.amazon.com/Capacitor-Round-volt-Z97F9042-97F9042/dp/B005DST0V4

It is spec'd at 42-55uF-- which is ~47uF +/-20%. You may find cheaper sources elsewhere.

2) Tolerance and uF values are completely independent. You can obtain std cap values with Typical tolerances are +/- 1, 5, 10, 20%.