Hi Adrian, Welcome to the Forum,
Of the Tanks you have placed on your wish list, Most of us at some time get ourselves a Tiger 1.
It is probably a better choice for a first Tank because it is first of all great value for money, It is available with a metal hull and it has a lot of upgrades available, There is a lot of internal space which makes any work you do less likely to cause broken connections and because most of us have bought/built one+ we can help you with any questions you might have,
The PZ 4 is a great Tank, again a lot of upgrades are available,
I am a little puzzled by your doubts on the width of its tracks,

You should have a look at British Tanks of that era.

Remember it was a medium Tank and until the T34 and the German copy the Panther came along all medium Tanks tracks were quite narrow.
I offer a word of advise about the PZ4. It is all Plastic/ABS, 1/16 r/c tanks benefit from having a metal hull and it is the only German Tank of WW2 that does not offer a "DECENT" metal hull as an upgrade, "ASIATAM" sell a PZ4 Metal hull and from personal experience and that of other members of the Forum I would give it a very wide berth.
Enjoy this place we do.
Shaun.