Ordinarily, you want to tune for spine before you tune for porpoising. I recommend you shoot a bare shaft and see what's happening. If you're not getting a lot of nock-right or nock-left when you shoot the bare shaft, then see if you're getting nock-high (compared to a fletched arrow). If you're getting nock-high, then gradually lower the nock point until the bare shaft is hitting the target at the same angle as the fletched shafts. A little nock-high is okay.
On the other hand, if you're getting nock-right with the bare shaft, it means your shaft is too stiff for your bow. A little too stiff is okay, but if it's way too stiff, that's probably a worse problem than your porpoising.
Shooting bare shafts is simple to do, and tells you a lot about what's going on. It should be easy, since you made up the arrows yourself anyway. I save a bare shaft from every different batch of arrows I either buy or make, and after a while, you have enough set aside that you can easily determine what you need for any new bow you buy or make.
OTOH, it's not going to hurt anything if you just lower your nock point 1/8" and see if you like the arrow flight better.