Can't Tell The Overijssel Ducats Without A Scorecard (Namely Delmonte)

Having recently obtained a copy of Delmonte's Le Benelux d'Or (1964), I am working on improving some of the Numista catalog listings on certain Dutch types with multiple Delmonte catalog numbers.
Nope, these are not coins I will ever be able to add to my collection.
It's an act of (nearly) pure altruism , though it gave me a better understanding of this type, and an appreciation of the fallibility of auction houses (and maybe even the author).

First coin I tackled was the 2 ducat (dubbele dukaat) of the province of Overijssel struck between 1582 and 1593, commonly called the Spanish type for obvious reasons (also Friedberg 261).



Delmonte identifies 4 subtypes, numbered 1043-1046, all of which have the same main devices, and more-or-less the same legend, but are differentiated by the presence and location of these four marks: city gate, hook, lion, lion of Overijssel:



So, for example, looking at the full coin images above, we see the city gate at 12:00 obverse, and the hook at 6:00 reverse, which identifies the coin as Delmonte 1043. Delmonte 1046 had the city gate at 6:00 obverse, and the Overijssel lion at 6:00 reverse, and so on ...

Using acsearch and searching on the Delmonte numbers and/or Fr 261, 24 sales can be found, which break down as follows (Delmonte's rarity ratings):

Delmonte 1043 (R1) - 9 sales, of which 4 mis-attributed and 1 not assigned a Delmonte number
Delmonte 1044 (R4) - 3 sales, all of the same coin
Delmonte 1045 (R1) - 1 sale, mis-attributed as 1046
Delmonte 1046 (R4) - 8 sales, of which 3 misattributed. Additional 3 sales of coins that might be considered 1046 variants.

Two things stood out from the analysis:
1. Of clearcut cases (not variants) where a Delmonte number was assigned, 40% were assigned incorrectly. Places like Stacks, Heritage and Kunker made mistakes. Places in the Low Countries (Elsen, Heritage Europe) did not.

2. At least one of the rarity assignments by Delmonte requires revision. He assigns R4 to types where 2 or 3 examples are known, which could not pertain to 1046 (maybe this is a known error in the catalog).

Lastly, netiher Delmonte nor Van Gelder and Hoc identify the mint to Kampen, though the city gate is known to signify the Kampen mint on other Dutch coins of this era, and it's known the Kampen mint was striking other gold types (nobles and other ducats) around this time. Perhaps there is documentary evidence on the other types, but not on the 2 ducat?