Hi,
nice minis so far.
We have played the scenario quite a few times (the pics portray the game at Milano Wargames con held on February): most of the times it went as happenend in 1289, with a Guelph victory but always hard fought. The Ghibellines usually have no problem in destroying the first line of the Guelph cavalry and mauling badly the main cavalry force. Their infantry has good chance to destroy at least one of the "companies" holding the Florentine flanks, but the counterattack by Corso Donati usually saves the day for Firenze.
Actually it's very hard for the Aretines to win: they are outnumbered nearly 2 to 1 and they choosed to attack. To give them some chances we powered the quality of their cavalry (it has some historical consistency) and of their commanders (Buonconte da Montfeltro above all) and we divided their army in few forces, more numerous than the Flontenie ones, harder to break. If you trust enough Google Translator you can read the report about our scenario in my wargamesgroup website (shame on us it's still no pics)
http://gruppoludicoaglianese.it/nuovogla/2019/04/03/campaldino/About the Siena's contingent it's testified its presence at the battle since Siena had suffered a regime change, becoming a guelph ally for Firenze after their defeat at the battle of Colle Val del'elsa in 1269. For the senese contingent we have used the heraldry of their "Podestà" (Major) Tomaso di henzola and of some families of the city's guelph party. Their infantry is also quite interesting to portray since it had a sort of protouniform: every "terzo" (district) had it's distinctive overcoat colour, if i remember well green (Città), red (San martino) and white on black (Kamollia).
If you need some advices for heraldry please jus let me know, i have many images that we used for our project.
Cheers.