I'll try:
Using Montanari for Libya:
Two battalions (gruppo) 77/28mm (24 guns total)
One battalion 100/17 (12 guns total - increased by another 12-105/28 in North Africa in 1942)
2-3 sources will claim 8-100/17 versus 12. The argument works like this: All armies used four gun batteries whether British, French, German, or Italian. A battery worked together against the same target or in support of the same friendly unit. For example, an infantry regiment of three battalions was supported by 4-47mm guns (called a company) and 4-65mm guns. Each of the three battalions were supported by 4-77/28 guns or 12 guns total of 77/28 which, for two regiments of infantry, becomes two battalions (called grupos) or 24 guns as above. Originally, all Italian divisions were triangle divisions of three regiments and each regiment had one battery of 4-100/17's (or 105/28) or 12 guns total.
When binary (two infantry regiment) divisions were created, logic dictated each regiment, should have 4-100/17 guns or total 8 guns per division and not the 12-100/17's shown above. When a triangle division has a regiment of infantry taken away (leaving a binary division) the regiment that leaves takes 12-77/28 guns with it (A triangle division would have 36-77/28 guns.). It should also take 4-100/17 guns with it. To not do so would mean the new binary divisions created had 77/28 guns but no 100/17's. Hence, the assumption was made that 4-110/17's left and the new binary division had 8-100/17's.
Not only does the math work but to leave a binary division with still 12-100/17 guns meant that 4 guns had to to be added plus their transport, ammunition trucks, and artillery men so that was one problem. Another was what does the added battery of four guns do? Unlike the other 8 guns, it has no infantry regiment to support. So some sources assume Montanari made a mistake and the number of guns 8 and not 12.
To determine which was correct, I game tested Italian divisions in N.A. and it showed the Italian divisions had 8-105/28's or the possible right number but the wrong gun. My explanation is that 12-100/17's were used but, being an inferior weapon, showed up on the tests as 8-105/28's. The 100/17 fired a 31 pound shell for a range of 9,100 yards versus a 35 pound shell for 13,100 yards for the 105/28, making the 100/17 at most 70% as good and probably less. 70% of 12-100/17 is 8-105/28.
So I support Montanari even though 12-100/17's creates a gun directory mess. There were enough guns available to do this though and even enough 105/28's to replace all the inferior 100/17's.