PSP Novice - Essential Questions

Hello fellow mellow permies --

I have nearly finished excavating the Royer Foyer of my underground dwelling and it suddenly dawned on me that I don't really know what I'm doing. Yet I fear not. Hopefully you guys can help me out.

Here we go:

Q1: What kind of shoring does one recommend using? How about the shoring's length, width, thickness? There's a bunch of well-dried, felled timber on the property, but I'm not exactly sure how to use it, and I'm using hand tools only. I thought using dissembled pallet wood might be an alright idea, but I suspect it lacks the length required to connect posts.

Q2: How much space should there be between posts?

Q3: Would a post depth of two feet be sufficient in stable soil/clay earth, or is more depth required?

Q4: I'm aiming for an eight foot ceiling throughout. What is a good length post to use, taking in account the girder and post-hole? 12 feet or so?

That's all I got for now. Any help would be greatly appreciated. Thanks heaps!

Greetings, and welcome to permies Damien!

I cannot give any technical advice on this, like you are asking for; however, while you wait for someone to come across your post and answer your question, the first wofati thread, Paul Wheaton's wofati article, Mike Oehler discussion thread, or one of Paul's podcasts located here, here, or here may be of use.