Linking Plat of Zion I and the explanatory Letter

I finally managed to match up this plat of Zion from the summer of 1833 

with the accompanying letter in the Joseph Smith Papers collection (“Explanation of the Plat of the City of Zion,” ca. 25 June 1833; handwriting of Frederick G. Williams; in JS Letterbook 1, pp. 38–41; JS Collection, Church History Library). An alternate transcript can be found here.

Among the noteworthy things to learn from the letter are:

• (p.39 letterbook == p.2 scan) The red squares in the middle are to be interpreted as follows:
• The empty square is for stores for the Bishop. 
• The 12 "squiggles" in the middle are circles that represent temples for the Presidency.
• The 12 "squiggles" in the right one are also circles that represent temples, this time for the lesser level of priesthood. 
• Note: A closer look at the squiggles reveals that their strange structure is due to the fact that the circles are numbered. This is confirmed by the letter (p.40f letterbook == p.3f scan)
• Middle square circle #5, which appears extra smudgy, seems to be the temple marked with a cross that the letter mentions (p.39 letterbook == p.2 scan); my research friend Zomorah seems to agree. 
• The structure of the temples were described in a separate document.
• The temples all have names and designations (p.40f letterbook == p.3f scan), and the 5th temple is among those named "The holy evangelical house for the high Priesthood of the Order of God 
• The often cited rule about the alternating house rows is clearly described (p.39 letterbook == p.2 scan) but actually violated in the corners of the map; only the 2nd plat of Zion will fix that issue, but make additional changes as well (see below), including to the temple. This is one of the things that Zomorah got wrong.
• (p.39 letterbook == p.2 scan) The letter computes that for the 15 to 20 thousand people that will be able to live in the city, they will need 24 churches and schools. 
• (p.39 letterbook == p.2 scan) The barns and stables are to be located at the northern and southern boundary of the plat, which means that no barns and stables need to be inside the plat.
• (p.40 letterbook == p.3 scan) The North and South will also hold sufficient farmland to feed the plat through the work of the "agriculturalists". However, the East and the West will be left to house the next plat, so that the whole of the City of Zion is a thin band of these plats rubber-stamped next to each other "in these last days and let every man live in the City for this is the City of Zion" (ibid).
• (p.40 letterbook == p.3 scan) The houses are to be built 25 feet back from the street, with "a small yard in front to be planted in a grove according to the taste of the builder", the rest of the lot for the garden "&c". Houses are brick and stone only. 

Note that the text as preserved in the letterbook is more complete (since the plat is torn around the sides) and the secondary copy, thus containing corrections that Frederick G. Williams made. It therefore cannot substitute for the writing around the plat, but is a "second edition".