When I was speccing a frame some years ago, I asked Mr Yates about where the bottle should go and he was quite adamant that it should be to the front of the forks. #
Well. I didn't take his advice. And then I spec'd a frameset from another builder - with a bottle bracket at the back of the right fork. Problem was, when I received that frameset, I really really didn't look the like of the brazing of that bracket. There wasn't enough brass filler shouldering the bracket to the fork (there was under-hang of the filler), which would increase the stresses going through the joint. The builder didn't seem to agree, BUT STILL changed the whole fork, so fair enough. The replacement shouldering was much, much better - but should have been like that in the first place IMO.
The point is, you do take a bit more risk in having the bottle on the rear of the fork. I suppose That was doubly so, having a Lightspin bottle, which is perhaps twice the size or weight of a regular bottle.
Edited for nuance