Let me state that assembling 8020 extrusions is quite easy... even for complete noobs like me. if you've played with lego, you can do this... so fear not Noobies!
one thing to keep in mind is to plan out where and how you're going to attach the pieces together... you have to pretty much slide the cross members in advance or have the nuts placed in advance.
while most of the assembly can be solo'd... i found that some parts, it helps a ton to have someone to assist.
since i have assembled the upper portion of the base, installing the bottom horizontal rails was a bit challenging.
i pretty much connected all 4 pieces, and then slid them into position with the help of an assistant.
not sure but i think complete kit comes with pre-drilled holes to drop in the nuts later on... but i chose to source my own so...
I opted to go with a 1515 for the lower cross member while keeping the 1530 to connect between the legs... using 8 hole bracket to fasten together.
anywhoo, hmm... giving thumbnails a try...