that is why you enter paris and therefore kick - off the 180 day period early.
That doesn't work. All it does is waste 2 days of your precious time in Schengen. The 180 day period is fluid, you cannot "start it". For calculating time in and out of Schengen you have to count forward and backwards 180 days from each date of entry and exit and see whether your intended travel inside Schengen within this period exceeds 90 days. That is why you have to stay outside the Schengen Area for 91 days if you want to get the full 90 days again.
If the 180 day clock resets every time you enter then after 6 weeks in croatia the clock will reset
Again, it doesn't work this way. The clock of the previous entries is still ticking and days are counted. See my calculations above.
For example if I have a WHV for germany and I spend 60 days touring around can I then spend 90 days touring in a shegen area or can I just spend 30?
The gist is that you are allowed to tour 90 days in a 180 day period in all Schengen states (just like without the WHV), with days in Germany not counted. You have to return to Germany or stay outside the Schengen area once the 90 days are up. So how does the WHV help you? Well, it makes your stay inside the Schengen Area legal for up to a year. With the WHV visa in your passport nobody (except the Germans) is going to bother too much with where exactly you spent that time (unless it is more than 90 days in a country that is not Germany). The German authorities will have some say about it if you stay away from Germany for more than 180 consecutive days, but apart from that you shouldn't have any problems.
To make you understand the problem better: If you stay for longer than 90 days you are not a tourist, you are a resident, have to apply for a residency permit and pay taxes. That's why the 90 day rule exist. Per Schengen Agreement you cannot get a residency permit for the whole Schengen area, you need to apply for a residency permit in one of the countries that signed the Schengen Agreement. Where you should apply for a residency permit usually depends on where you intend to spend the most time.
(If you planned to tour the USA in a campervan for a year you'd have more or less the same problem. )