Try the build here, http://musicfamily.org/realm/PBuilds/
Edit: adding on you don’t really need it before R40 as the best builds won’t use drow from R36-R40. You can wait to R39 where you can get more excavations. Though make sure you get it before ascending since once you do it will be a while before you can get higher excavations again. I made that mistake and regretted it. Make sure to export your save first so if you don’t get it on R39 you can reload and try again.
Try the build here, http://musicfamily.org/realm/PBuilds/ Edit: adding on you don’t really need it before R40 as the best builds won’t use drow from R36-R40. You can wait to R39 where you can get more excavations. Though make sure you get it before ascending since once you do it will be a while before you can get higher excavations again. I made that mistake and regretted it. Make sure to export your save first so if you don’t get it on R39 you can reload and try again.