Suggest you add a little yellow to the white to make a pale cream and paint the haversack and strap light buff to make a difference. Haversacks were usually canvas and the belts were whitened buffalo leather. The pale cream will look as though they haven't been blancoed for a couple of days. It is always a good idea to remember the material of the item you are painting. For example a Guard Grenadier has a mass of white on the front, lapels, crossbelts, waistcoat, trousers and gaiters. The lapels and trousers were of quite thick cloth so paint these light cream. The belts were blancoed so paint them dead white, as also the waistoat and gaiters which are of thinner material. The subtle differences in shades will enhance the figure. Trooper