Your present set up may be enough but.....still some like trying things different, or just want more FOC
Since you didnt mention it, Im assuming these are wood shafts?
You can pick up some 75 grain or 100 grain woodyweights, 3/8 and 1/2 inch in length respectuflly.
Only a test arrow will decide if cutting back an inch or so, give or take, and adding these will weaken the spine too much.
Another option is to internally foot them (drilling a center hole in the shaft and inserting weight). There is a tool here for doing so. I like this option simply because the amount of weight is entirely up to you.
http://www.braveheartarchery.us/new_page_26.htm Of course just trying a heavier head would also be an option as would adding the woodyweights or larger head to a bit stiffer spine if one is needed.
Just my 2 cents.
God Bless