I replied to your email/pm and saw your order but for everybody else the headlights are 90mm but you don't want to use a 90mm boot as it might be slightly too big and fall off.
85mm is a good size, or 83mm (I sell the 83mm since my source was out of stock on 85mm and it's so close in size).
83mm fits great. Does not fall off and allows you enough room to get the boot over. An 80mm will even fit, i've tested that so if you can't find 83 or 85 an 80 will work. Requires more effort but fits.
So in the end, 80, 83, 85 are all good choices. 90mm if you have NOTHING else (you may need a zip tie around it to secure it though)