Like cbbram says, the pinning, especially with a pen is much less of a process than any kind of IM. Almost always no feeling, never any blood and the whole process takes about 30 seconds.
I personally don't think you need to split until after you push past 4 or even 6iu of pharma hgh just due to how most of the hormones and other growth factors that are released with the use of hgh are generally very long acting. Opinions definitely vary on this though.