I've done Crota like 15 times and I keep getting Energies. Your logic in soloing a couple checkpoints just to get to 32 is bogus. There are some people playing this game who commit time just has much as the "glorified" 32s, who don't get the RNG love to get bumped up to 32. You have to complete the full raids to get the goods in line for a 32. Soloing half raids every week will get you nowhere. It took me a two months just to get my boots.