Fiber fractions in the 55% range are consistently echievable with RI methods. That's certainly good enough. Autoclave is not really applicable to the construction of most beach cats since they use foam cores. Autoclaves are only used when you want compaction pressure greater than one atmosphere. The lower density cores do not do well with ths type of pressure, especially at elvated temperatures. Autoclave copaction/curing is the territory of the Nomex honeycomb cored boats, which is to say, the high-end boats. I have managed to crush some of the lower density PVC foams with only a good vacuum at room temperature.

One small problem with RI is that it may tend to oversaturate certain areas of the dry stack-up, like the edges of scrim & score foam, or corners where foam pieces meet together. In hand layup, these would be hollow voids, which is OK since it is in the core anyway. But with RI it winds up being solid resin. Stronger? probably, though not in any meaningful way. But certainly heavier by as much as a few pounds per hull. There is usually a simple solution in changing certain details of the core to avoid these resin pockets.

Jimbo