Scott, my procedure is similar to yours.  Getting the main unfurled is helpful and easing the sheet is vital, although there is a point where easing it too much results in the sail coming down twisted.   I lead the snuffer line to an opening block attached to the Leeward forward mooring cleat with a soft shackle and pulling through that block, I’ve not needed a winch to pull down the snuffer.   If you don’t have the block, you cannot really pull effectively and a light person risks being hoisted up by the line!   I’m having the snuffer line lengthened now so I can get it on one of the cockpit winches when necessary.   As it was, I could put it on the anchor capstan but it was not long enough to reach the mast winches.  I want to be able to pull the snuffer down from the cockpit, which could be a big safety factor.  

On your other point, I fully agree.  It’s very important to make sure the people doing the work have done the specific work before and have an excellent reputation.  And you or a third person whom you trust must check the work carefully.  I’m having Lithium batteries installed on my boat by the local Mastervolt dealer.  At the end, a Mastervolt technician will travel to the boat and certify the installation.   I’m hoping that is being careful enough!  Cheers. Joerg