First, thanks for all of the posters here that give out great info...I've read the seciton quite a bit in preperation for my first two builds but still have some questions.
I'm thinking of doing a Romy G for my first build as it seems to be a pretty inexpensive, popular, and well documented build. I'd like the first one to not be worn out too much. For my second I'd like to do some sort of inexpensive underfolder...it will get beat around so it doesn't have to be anything "special" at all..just something that works and folds up somewhat smaller.

So my questions:
-I can't seem to find information on what receivers I should be looking at...I think that I want an NDS-3 for my Romanian build but would take any advice that you may have if I should be looking at something else that might make it easier on a first timer.

-I keep seeing references to "single hook" and "double hook" triggers...anybody care to explain the difference to me?

-I have no idea what I should be looking at for either parts kits OR receivers for build number two, but I'd like to buy the parts at the same time as I buy for my first build...to save on shipping if possible...so what's the best road that leads to a beater underfolder? (here's where my lack of knowledge of AKs will REALLY shine)...is it possible to fit a folding stock to one of the Romanian G kits or do I need to buy a parts kit that has a folding stock? What receivers am I looking at for something like this?

FINALLY, Any recommendation for my parts? I'm looking at the following...so any horror stories, or am I fine going with any of these?

Receiver:
NDS-3 from Nodak Spud $55

Parts Kit:
Copes Hand Pick $114.99
Copes Hand Pick + G2 $134.99
AKParts.com Hand Pick $119.95
EE "new" for $115
www.ar15.com/forums/topic.html?b=7&f=123&t=404217
EE for $95
www.ar15.com/forums/topic.html?b=7&f=123&t=399281&page=1#bottom

Thanks so much for your time! I really appreciate all of the questions that you guys answer...especially when you have to answer some of them over and over again...I tried looking up these, but couldn't find my answer...but for all I know they have all been asked a million times so sorry for that part.

My 1st Romy build was on an OOW receiver, 2nd Romy was on a NDS-3 receiver. The NDS-3 was by far the easiest of the 2 to build on. Not having to drill the holes for the trunion saved alot of time and the holes actually lined up.

I bought the Kits from 2 different places. 1 was from Copes top of the pallet random selection - $85 special. The Copes kit was all matching. The 2nd kit I bought came from Bocephus (EE seller). I bought it 2nd hand with the OOW receiver. The kit was non-matching.

I used Tapco G2 double hook triggers on both. I traded some mags for 2 sets of trigger groups on another forum.

Rivots and US slant brakes came from Copes. Gas pistons I bought from Armory USA.  

Right now I'm building a Yugo Krink Pistol 7.62x39. For that one, I'm using a NDS-1 receiver. No SBR allowed in IL. Since I'm going to have the stock left over, I'm also going to build a underfolder Romy.

Bought a NDS-1P receiver for that one. Now I still need to buy a underfolder trunnion & found one that I hear others have used successfully on this NDS-1P receiver here:
Gunbroker

Yesterday I picked up just about everything I need for the under folder from Copes.
Comparing prices with DPH, Copes came cheaper shipped. Bought $99 Romy kit, gas piston, and a slant brake. I still will need a set of hanguards but will think about that later. May just cut the romy foregrip off.

Not sure if this answers any of your questions. But a couple thoughts, don't be too concerned with the finish of your Romy kit since part of the fun of building these kits refinishing the gun and stocks once it's built.

Here's my 2 kits finished. Will post pics of the Krink and underfolder once they are done.

Top is OOW receiver bottom is NDS-3.