My bike has always been hard to start on cold mornings, particularly at or below freezing temps. I also developed the "click" problem which happened when it was very hot or when it was very cold, but had been coming more frequent (at least once per day) recently. I tried various batteries (of the "normal" type) but it had little effect. Some others have had this problem, whilst many others have never had a problem. I always thought that there must be some small difference between the bikes to cause this. I have not installed heavier battery cables or the additional ignition relay system.
However, a couple of weeks ago I had a problem develop with the big 30 amp fuse. What I discovered was that the slot for one side of the fuse (in the fuse box) was larger than the other side and so the fuse was not connecting as well as it could have been. I widened the fuse leg with a layer of solder and put it back in. Since that time the starter has never "clicked" and the bike starts easier.
It may be that something as simple as variations in the fuse box have been causing all of the hard to start problems we have been experiencing.