Since you may not shoot JG matches, take this all with a grain of salt.
In regards to Military standard 30 cal ammo, there are two types of bullet tips. The first is 150 Gr FMJ flat base (30-06), and was designed for the garand rifles. Laters came the M-14, and the ammo for the became 147 FMJ boat tail (308/7.62 NATO).
Now on the standard USGI garand barrels, the throat is set up for a bullet jump to lands, and most often, the flat base 150 gr bullet will out-group the 147 gr boat tail design (using the same loads/differnt type bullets in the 30-06 cases). Because of this, when reloading for the garands using stock USGI barrels, the 150 Flat base is the better choice of bullet tip than the 147 Boat tale.
Now in regards to ammo (read stuff to shoot in JG matches If I have to shoot "factory ammo" and not reloads)), My first choice would be the CMP surplus ammo, then depending on the price they may be gouging that month, turn to korean PS stamped ammo. With good surplus ammo avalible at a cheaper cost over current production, I would just stick with it until the sources drys up, then start looking at new produced ammo. To sum it up, it all just comes down to what prints in the rifle, and what will not. If you have the funds, buy a little of all of current offerings, and start printing groups to see what the rifle likes.
By the way, the current LC ammo offered by CMP is a smoking deal.
estore.odcmp.com/store/catalog/catalog.aspx?pg=product&ID=405&item=&sfv=&cat=AMS&desc=&udc=&mct=&vndr=&ba=&pmin=&pmax=¬e1=¬e2=¬e3=¬e4=¬e5=&max=Here is a source for Korean PS ammo (non-crossive with clips, the ones on the bottom of the page) just incase your can't order from CMP,
www.aimsurplus.com/acatalog/copy_of_30_06.html