Foliage tool lightmap density where?

Hi
Win 10
Ue4 4,22.3
I cant find the lightmap rez. According to the web the setting is in the foliage tool. But where? Its probably staring me in the face. Anyhow, under the viewport dropdown for viewport states/ optimization viewmodes/ lightmap density the viewport shows foliage instances in red. Under the tool I cant find the settings for the lightmap. Building lighting takes forever after inserting about 15 tree instances. Any assistance appreciated.

Cheers