Oh... I can share a bit.
After a few days of struggle....
Made a third floor floor with the 3 story pillars.
Placed some floor.
Removed the pillars.
No walls yet.
Added a deck right next to the third floor.
Used "Boolprop constrainfloorelevation false" ; and dragged the deck surface up to the third floor.
Keep this on until your ramp is built.
Then raised the ground under the deck, sloping it upwards to the third story.
There has to be steps to walk up the ramp to the 3rd floor.
I never tried this, but when you select shift and place a deck on top of another deck, it makes a new higher deck.
Also works for making a multi leveled floor.
The walls adjust, and are 1/2 the size of the half wall option.
Tried this to put a fence on top of another fence, but it hasn't worked.
" Inama Nushif "