Re. running through the PAO palace beforehand. Actually, when I started out, I reviewed the palaces on a scheduling that followed Dominic’s rule of 5 reviews. (+1d, +1wk, … etc). I did that because it was slow. At first, I had to “try” to recall the path way through the palace, and even refer to a hand drawing sometimes. I would track the reviews by putting due dates and check boxes on the palace drawing, along with how many I forgot PAO + Loci is 400 things to recall, so I would score myself out of 400. Over time, the forgetting decreased to zero. Also, after I dunno, 10 reviews or something, it became super fast, with no delay at each loci, it was like visualizing something you know incredibly well, so entire stations (with many loci) such as a room containing 15 PAO characters just, pops into mind as one chunk. Now to review 100 loci in a well known palace takes 1-2min.
I think these are all different skills that need their own practice: making palaces, reviewing palaces, and random recall and translation.
Re. tracking speed. Yes, but really informally. I check my anki deck stats for cards per minute in my memory deck. I also track the speed to memorize a deck of cards. I’m slow, but every time I do it, it gets a tiny bit faster.