Build system, roof placement issues

So this is what I got so far, a click and drag build system set up for multiplayer.
As it stands now the roofing is made out of “stilts” , wich you can click and drag up or down.

Problem now is the maths, and how much there should be, and what parts should be done manually by the player.
Id like for the player to skip having to connect all the corners manually.

At the moment im gonna make sure that the highest, calling them “middle stilts” are all facing into the room. And it begins to check if two forwardvectors are facing eachother in a straight line. Then it connects those two as sort of a main beam.
Could even have that as a must-have for a roof to be valid.

Its pretty cool because when you build your house, you name it. Server keeps track of rooms and so whole houses and properties. If a player enters my house and I named it “moo” it would notify the player he/she entered the house of moo and if the player was allowed to.
And it lets players have alarms that warns them whenever someone is in their house if it was locked etc.

The server could even notify the player in what room they are in