Fungus is mainly a problem in tropical climate. So unless you are going to store your gear in a hot, humid & dark room while in Europe, you won't have a problem. I assume you will be out and about taking lots of photos, right?
Sorry I not not familiar with dry box availability & pricing as I only use dry cabinet.
I assume you will be back in Singapore after the germany trip? If yes, I suggest you just buy a dry cabinet such as the Digi-Cabi. Get the DHC version. Cost a bit more but much easier to set the humidity level and I believe it maintains the humidity setting more accurately than the analog version. And don't make the mistake of thinking it is too big (unless you really have no space for it). I initially bought the 40 litre one and ended buying another larger one. This was exactly what the salesman had predicted.
I bought mine directly from digi cabi. They have most of their models & sizes on display so you can check them out first. The owner is a real friendly guy and they deliver free of charge.
Formerly: Markono Districentre
50 Tagore Lane (S) 787494