Nice sb alexsimon
Right: the ALL_hud.def is used by all the sb.
This file is included in each specific "XXX_hud.def" in which you can define specific values in accordance with the sb XXX.
I think you should create a CHGR_hud.def file (if not already created) and in this file define the size and position of your challenger logo.
If you want to modify other values, be careful because some data in ALL_hud.def depend on other ones.
Thx for the logo!
Can you also send the others icos (games, set, ...) but when you think your sb is done and if you are ok!