cull one site of extrusion, merge extrusions?

hello,

as you can see i try to offset some surfaces, but i fail all the time. :( 

i don't know why, but some direction of my surfaces are wrong, so i disabled the absolution battery and extrude the surface in both direction, to cull one side. but i can't find the right definition for that.

the other question is, how can i merge or fillet the extrusion to one volume?
or is my entire definition wrong and there is a much more faster and better way?

i'm really happy about every answer! 

thank you all really much and please forgive my bad english and my stupid questions, but i really want to learn grasshopper und i try every thing before i write in this forum!

max