some details in Zadi of Reb Reuvens csav
Here are examples of Zadi Pshuta I have scanned of Reb Reuven Sofer.
1. In the word (ארץ הכנעני) one can clearly see that R"R writes the right yud first, as a straight yud [as in csav beis yosef] except it doesn’t have a regel. Only, after writing the Nun pshuta he connects the yud to the nun, with a line (which doesn’t look exactly a regel for the yud of Ari-zal) and the connection is a bit inward – not from edge of oketz of the yud, so both yudim are somewhat visible.
2. The upper right kotz of the yud is added after the initial writing of the yud, just as the kotz that connects the yud to the guf of the nun is added later. Sometimes we can see that he pulls the kotz all the way down the right side of the yud (see חמץ), so there will definitly be a kotz on both top and bottom of the yud. Now, this yud has 4 kotzim at its 4 edges, an exception to all his yudim wherever that have only three kotzim. I found a source to this unique feature of this yud in Zohar and Ari zal's Shaar Mamarei Rashbi.
An explanation for these kotzim on the right side of this yud, I understood from Zohar and arizal, is so that this yud has 'panim' facing both sides looking to right and to left.
This (is also to prove what I wrote in a comment in regard to the rosh of the vav) explains, that in R"R csav, the left side of the letters always open in a semi-circular indent starting and finishing with sharp uktzim, but the back of the laters [the right side] are usualy rounded somewhat [although there are 2 exceptions – the beis and mem sofi]. These kotzim indicate the face of the letter, so in this yud there are 2 faces, one facing the left [the beis yosefs yud] and one facing right [the arizals yud].
3. But I don’t know if he made the right face of the yud (kotz al panav b'ymin) before the connection to the guf [nun] or after. I think he did it last.
4. The left head of the Zadi is extended/wider much more than the right one, usualy twice wider [sometimes even more], it also has a very slight tilt-upward slanting the head somewhat so it isnt exactly alligned with the right head.
All these 4 points are correct in regard to the zadi k'fufa as well.
5. In the Zadi k'fufa one can clearly see that the neck (tzavar) does not start at the very edge, but a bit inward.
The neck starts coming down then bends clearly to the right, and is never one straight (slanted) line. This is learned from the gmara shabos 104 הוסיף כפיפה על כפיפתו that the Zadi (kfufa) has 2 k'fifos (this and the bend of the moshav).
6. In the word חמץ the connection of both heads of the Zadi meet where the foot starts to become wider, so that they are almost equal in their connection. This picture is called by Rabbi Landau's [shlita from Bnei Brak] Lishkat hagaha a מספריים (scissors). He claims since it isn't evident which part of the Zadi is dominant, IE is the right yud connected to the guf [the nun] on the left, or the left yud is connected to a right guf (therefore inverting the zadi to a new combination, instead of nun yud) and is pasul. I don’t accept this chumra at all.
7. The guf of the nun pshuta doesn’t descend from the center of the head but from the right side as most heads of שעטנ"ז ג"ץ, unlike a nun mamash that discends from the center. (In his zadi k'fufa it is definitly towards the right but not mamesh at the edge).
The guf is clearly slanting to the right, till it ends under the right head, and not straight down as in csav BY.