I've ordered a flight pack with the GWS mighty micro servos, i just got conformation that it shipped today, so, i hope to have it Friday.  Since i don't want to continue the build until i get the flight pack, i'll post  this link to a funfly i built some time ago, with very thorough instructions.  
The rest of the build is almost identical.  
Here's the jist of how i do it:
I install the radio gear into the wing, and fuselage, and install the landing gear.  tape the battery as far forward as possible, then tape the wing to the fuse, until i find a fairly conservative cg. (usually 25% mac).  Thats how i determine where to cut my wing in.  
Then i make a template of the wing root, and trace it onto the fuselage, and cut it out.  Remove one aileron servo, and slide the wing through the fuselage, with the aileron  flipped up over the top of the wing. (see the brickknife build link below).   Then,  i can move the battery back after i test fly it to find the correct cg.  

Here's the link to the Brickknife build:
http://www.rccombat.com/forum_2000/topic.asp?TOPIC_ID=6345&whichpage=2


here's a shot of the servo install on the fuselage, for the rudder and elevator:




Here you can see the landing gear, engine mounting, rx and battery mounting.  I use double sided tape, and zip ties to hold everything on, the same for the fuel tank.


and one of the throttle servo install, as well.



I'll finish up the plans for the final version, as soon as i get the rest of the parts in.  In the meantime, the info above should get you going.  

Cg ends up just behind the spar, but, start with it on the middle of the spar, just to be safe, then move the battery back.
On mine, the leading edge of the wing was cut in 7 1/4" behind the front of the fuselage.