I absolutely didn't mean to post yet, I wasn't completely finished writing and adding pictures instead of preview I hit post D'oh!.!
as for the sleeves, I pretty much figured it out while splicing 2 tshirts together so it's kind of hard for me to explain....so I made a graph..
the gray material was a hanes mens medium I brought it home from the store and found a hole in it so i threw it in my scrap pile...I guess you could make up your own pattern if you have other fabric in mind besides another existing shirt.....I made a tube shirt and attached the sleeves like this
haha I know it looks silly but let me describe what you're looking at....
the view is as if you were looking down into the black shirt tube the green is the side seam and the gray is the sleeve tube...the front is clearly labeled as such
sew the armpit to the top of the tube...I did a longer seam in the front (about 5" from the side seam) than the back (about 3")
I tried to explain it the best I can...I usually to everything by eye with little to no planning and rarely use actual measurements
and please excuse my terrible face in the picture...it was hard to get my boyfriend to behave and take a picture of exactly what I asked him to