Remember you don't have to gather from the nodes if they don't have the hidden item. HW and above nodes come in 3 pairs. You go to one pair, open one node, close it if there's no hidden item, go to the next pair, open one node, close, go to the next pair, repeat. At this stage the first pair have reset and you continue until you find hidden items. In addition you only open the nodes that don't have a visible bonus on the bar when selected before opening, (things like Gathering Fortune +5% ect.) since the others have a chance to proc trait bonuses like +2 attempts or yield +3.

Generally doing the above you'll find hidden mats faster than you recover the GP for pick clean.

The same applies for gathering HQ items, such as herbs for grade 4 Tinctures. Reset for a yield +3 node, use Leaf Turn III and repeat.