I'm trying to get my perception up and I've been reading that the max perception on any given gathering point is 15%

Right now I geared to meet the requirements of Unspoiled Gathering Nodes which is 320 perception which gives me 1% chance to HQ.
I'm looking to improve this to HQ 15%.

Is there any formula or could someone recommend what they use to achieve maximum possible HQ percentage.

Thanks for the recommendations in advance.