No offence, but you need to do a ton more research. There are some really good sites about injecting.
I find quads are easy - you can use two hands and see whats goin on.
I find arse injecting hard having to swivil upper body around.
Shoulders are ok as are pecs(BE CAREFULL IF U EVER TRY THESE)
BUMP for you, hopefully someone will link you to the site Im thinking about, if not I'll come back on later and find it for you.
As for making your upper body bigger, dont rely on injecting the parts to make them bigger, it'll be temporary swelling mostly. Size will come from gym,diet,rest.....and from gear.