Hi Chris, here in Annapolis, my boat's rating for a random course is 174 spin, 183 non spin. For a W/L course, 177 spin, 180 non spin. That's with +9 for 106% RF headsail with suncover and with no adjustment for the prop. I replaced my fixed prop with a folding prop. A fixed prop would be another +9 adjustment. Numbers for J/24 are 174/174/171/171, with 150% headsail and no adjustment for RF or suncover.
Before adjusting shroud tension, check that the connections at the deck are correct. The lower shroud should be attached forward and the upper shroud attached aft. I use a Loos gauge for shroud tension. I don't recall the numbers, but I think around 12% breaking strength. Without the gauge, I would start with loose shrouds, tighten the lowers equally until reasonably tight, then the uppers. Tighten the lowers more than the uppers. Then go for a sail in ~12 knots of wind. Adjust shroud tension until just barely taut on each leeward side.
The spin provided with the boat is all purpose spin, not flat enough to considered a gennaker. It is also not full enough for deep wind angles. It's best at apparent wind angles 70 to 110 degrees. Also because it is cut for use on the furler, the luff is shorter than on a full spin. For racing, I have an A2 spinnaker which is much deeper and longer luff than the stock spin.