I am not aware of any way top specify the number of icons in the tray in blackbox. If you use SysBarEx (plugin) you hide icons by middle clicking them, they then are accessible throught the plugin menu.
I've been using bblean for a while and as far as I know, there's no way to hide the tray icons. As far as putting them in the context menu, there is a plugin called bbtraymenu that allows you to popup a tray menu from the context menu. You can find it here: http://zzbb.hp.infoseek.co.jp/