I have no graphic design skills, but here's some info for nothing...
Crusaders didn't have very exciting markings. The basic Crusader (i.e. the gun tank) only saw service in North Africa between 1941 and 1943. The Crusader AA saw limited service in the Normandy campaign.
In North Africa, every Crusader had a serial number (on the turret sides or back and front hull). Most also had a squadron sign on the turret sides (diamond for HQ, triangle for A Squadron, square for B Squadron, circle for C Squadron - the seniority of the squadron was denoted by the colour). On the front and back mudguards would often appear the arm of service marking (red for senior brigade, green for junior brigade, with a number designating which regiment it was) and a formation (i.e. divisional) badge, however these are frequently absent in photos. Some carried the white/red/white armour recognition signal on the hull front and sides (this was more common in Tunisia). Some Crusaders had names, but it seems to have been fairly rare.
Appropriate divisional markings for standard Crusaders would include:
1st Armoured - hippo
6th Armoured - mailed fist
7th Armoured - desert jerboa
10th Armoured - fox
The Australian 9th Infantry Division also used them for scouting - that would make a nice marking option.
Most Crusaders were a sand colour (often described as pale stone); a wavy camouflage of black was quite common, but some tanks had a more complex camouflage scheme of with brown edged with black over sand. Some had wheels painted out so that they could be fitted with a canvas rig designed to make them look like lorries. Crusaders shipped from Britain for the invasion of Tunisia were dark green (6th Armoured Division's were green). The interior was silver, not white. Crusader AAs were painted and marked the same way as other Normandy campaign vehicles.
