I was in this exact predicament a little while ago. What I found was that when I focused on the performance of my bows (getting the speed and flat trajectory from there), the arrows were no longer a problem. Most of the arrows I made were from 5/16" dowels, and were slightly too heavy for my slower shooting shortbows. With a slightly stronger bow, and revised building techniques and bow design (and more practice), I can shoot my 5/16" arrows with plenty of spped and acuracy. Let me stress this, small bow tips. A ton of perfomance can be picked up when bow tips are made very small. Most of my bow's tips are only slightly over 1/4" wide for 50lb (with Osage).
So, I would say, focus on bow performance.
Sean