How high is your peak/ridge planned for?
When I did mine over the last couple of years, I made sure it wouldn't be beyond a height I could reach by ladder or scaffold. Ended up being around 13' with 8' walls as i remember. From there, I was able to hoist rafters into place using a rope and pulley setup (not quite a block and tackle). I'd set one end on the wall top, then go up the ladder or scaffold, pull the ridge end into place, tie it off, then fasten/secure.
Did exactly what you are planning this past summer. Raised a pole barn and set trusses on 12' walls. Bought a 20' square pole for $100 and attached a Harbor Freight electric hoist. Allowed us to easily lift the trusses and raise them up and down with precision to set them exactly where we needed them. Supported the pole with chains attached to the front end loader mount. Built a jig to attach to the trusses so we could pick them up across multiple places so we would not damage or overstress the trusses. Screwed the truss to the jig so there was no chance of dropping the truss accidentally.
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