I know it is past time when input on overflow pipe is an issue. However, adding the experience of an infrequent sojourner through here. I have a pond about 0.4 acre. 11-12 ac watershed. I asked NRCS for input on overflow pipe size. They said 4". I didn't believe them. That is kinda pointless. We get some big rains here- 2-4" in a day. I put in a 12" pipe. And I have seen it running completely full twice. Seeing an overflow running max is scarey. Tis only my experience, but pay to oversize. The peace of mind is worth it.
Glad you are getting toward full pool. That is fun to see your dreams unfolding. Slow fill is better than fast fill.
