Hi Michael,
most contemporary drums that I've seen, and all that I own, receive nothing apart on the skin from the beating of a
Tipper and whatever crud comes from my left hand. From my experience, it's generally not necessary to apply extra stuff to a modern head. It certainly may be the case with older or cheaper instruments where the skin was essentially a rawhide and untreated for tone, in which case the relaxing of the skin is usually achieved by beating and the application of some 'goo' of some sort.
All drums will improve with playing of course and it's therefore useful to buy a drum that is not yet at its peak in terms of tone and which will develop with playing. Drums that are super-soft from the get go may have a reduced lifespan.
I've had a variety of my drums to the US (mostly Mid west or East Coast) at various times of the year and have never noticed any serious adverse reaction to having travelled although Air Con does definitely have an effect. However I remember Rob Forkner coming to stay with me for the first time and remarking how his drums seemed to react favourably to the Irish climate compared to the Texan air, CA may not be so different from TX in terms of the effect on drums.
I can't recommend putting a wax on a drum skin at all unless there are different grades than the ones I know and the wax can be worked far enough into the inner skin that it isn't tangible from the surface.
My own unfortunate experience of wax is that whilst it can polish up nicely and feel good when the skin is cold, it goes soft and sticky under hand heat and causes the left hand to bind, similarly wax applied to the front of a warm skin will cause the tipper to grip the skin a little. I found it off-putting myself but maybe there are variations of wax that will work and I've just not found them yet :)
P