First, I've been lurking for a while and just signed up. If this is the wrong place for this I apologize in advance. Posted a couple other places....some good some bad. Ingesting crew. Looks look in some threads who you are aligned to is more important to what you say. It wasn't this rough in 1980 walking Into a bar in Three Forks MT with a hillbilly accent....:)..

Looking at a couple different build options. I have a HK 556 and numerous piston system rifles. If I start with an 80% lower! what are the considerations I need to make if I want to build a piston and and tube system?  I understand the basics as I have both, but want to make sure I'm taking everything I can into account t.  Thanks in advance.

There are no special considerations for a lower that you're going to put a piston upper on.

No special considerations.
An 80% lower will accept either DI or GP with equal results.

Thanks guys.