thank you for your informative vid.

Very informative

Good video! Especially on roofs, a step by step procedure saves time, money, materials, those oh shucks moments, trips up and down the roof, and trips to town. If you start with the procedure first, then build material lists, tool lists, and cost estimates; you will have a quick check at the end if something was missed. I order 10% over, then check that at the end. If you are paying someone else, you can check at stages, and even contract and pay that way. For example, tear off, decking, and underlayment. If they mess this up, get rid of them, and hire another crew. Since most of the nails are blind, check usage often, and climb up there to make sure they are going in at right angles, especially if it calls for 5 nails instead of three. I can listen to the nailing, and tell if they are. Too fast, and they aren't going in square. In high wind areas up to 135 mph, roofing cement has to be applied the first 4 ft of shingles on all edges. Don't forget roof ventilation. If there are sags in the decking, it is insufficient, and new decking will do the same thing; pulling out the nails from underneath, and tearing off your new roof in sheets in a stiff wind.

Is it okay to double up starter shingles

should that gable end starter go over the drip edge starter? it looks like a butt joint

What if I ice shield is on top of drip edge

Too much needless talking.