but wanted to know how hard it was to line up the gas tube and bolt with the upper reciever? The lower seems straightforward on assemply and all I have to do is find some of the right tools to do it. Anyexperience in this area or tips on assembly is much appericiated

Side Note: reason being that I have chnaged around my AR so much I have enough spare parts around that All I need to do is buy the Bolt ,  and full parts for a upper & lower receiver.

This is kicked around a lot in the builder forum.  You should check out that area as I think your questions have been answered there many times over.

Its not hard if you have the tools and ability.

thanks

ar15.com/forums/topic.html?b=3&f=4&t=226782

read this; the hardest part (imo) on assembling uppers is gettting the FH to line up and taking out the pins on the FSB

if the AR gas tube has been used, some CLP to loosen the grime will help too