That's how I did ours with sheaves in the boom end cap. Took me a while to pull the lines through without crossing them inside the boom. Maybe that didn't matter.I'm not sure all H28.5's had the same system. On my '86 model, all I did was pull down the luff and hook the cringle to a reefing hook at the gooseneck. Aft, the reefing line ran aft along the boom, then up to a leech cringle, then back down the other side. Here is a generic diagram of that:
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