Not wanting to rain on your parade mate, but Loadmasters are getting as rare as Flight Engineers nowadays!!!
First off, you need know someone who is one and can also hire you, if not, forget it!
We use to have 14 of them 3 years back at Channex, now we are down to 2 part timers! and its all down to the bean counters.
Most loadies have now been replaced by dispatchers purely and simply for the bottom line, that is of course until the dispatcher breaks the a/c by tail tipping/ broken lateral locks,frames,stringers and cracked floor beams etc. !!!
So best of luck, and do some research on this forum about MK, as I am sure they only recruit Zims?
Freshline (A300s) in Germany might be looking next year, but so far all I have heard is talk, unless anyone else knows different?