I've started building off of a ledge that is about 2-2.5 (castle) walls high. I found a way to start it off by placing a castle foundation flush with the ledge somehow, and then switched over to pillar foundations. My problem is I'd like to build a structure on the ground level and have it connected to to original pillar foundations. If I snap a foundation to the bottom of a pillar, it is an awkward distance so that a regular wall will be slightly high and a half wall will be slightly short. Also, the bottom of the ledge is a slope, which complicates things further.

Basically, I'm not sure how to make a transition to the ground, so this is me asking for advice and making a suggestion to add more options to pillar foundations. I realize now I should've started from the bottom with regular foundations and built up, but nothing I can do about it.

Here are some screenshots...
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=676727706
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=676727747
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=676727767
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=676727784