Leave it to me to be eavesdropping on a couple of E-Scow expert sailors talking about the boats racing at the Geneva Spring Regatta. Here is what I overheard:
1. 60-70% of the boats were over trimmed going upwind on the first day of racing.
2. When the puff hits you have to easy the sheet to keep the boat from rolling up or heading up. Easing the sheet allows the boat to accelerate and then trim back in as needed to maintain the new speed. The adjustment doesn't need to be much to make a difference
3. Keep the boat steady on its lines by moving the main sheet! Never leave is cleated.
4. General rule of thumb is to have the top batten parallel to the boom. A slight easy opens the top of the sail and a slight trim will hook the top batten in.