After some research, I adjusted the positions that I had given both the Dutch and the English, in my Battle of Portland scenario. I had two books open, to help me better see how the squadrons should have been positioned and what course they should have had.
I ran the simulation, after that, and it was the case that the Dutch started off with an edge, as the relative positions dictated. If the Dutch would attempt to conduct a protracted fight, they would suffer. For a while, they seemed unable to damage English ships.
Next, I ran the Battle of Dungeness scenario. A winning strategy was to keep the Dutch in line, keep them at "arms length" from the English, and sail back and forth, on opposite tacks. One thing not to do is to needlessly spend ships by letting the Triumph fire broadsides at close range (or any range, if it can be helped). The last English ship afloat, dismasted, was the Triumph. I made the mistake of trying to sail, in the line of fire, and attempt to wear down the Triumph. All I got for my trouble was as half-a-dozen sunk Dutch ships.