If nothing goes wrong I should be in Bregenz, on the eastern shore of Lake Constance, by mid-July and ready for the "Austrian" leg of the E4.
As in Andalusia, at the beginning of the walk, there are two options - the Alpine or sub-Alpine routes. Originally I was keen to do the Alpine route but to be honest I'm now having second thoughts. Although the test run in July demonstrated that it is "doable", bits of it are definitely at the end of my comfort zone - bits of it are scary. It will also take a long time and the only itinerary I have found (Wikipedia) suggest 54 days and includes some incredibly tough days.
Information on the routes is hard to come by. Information is produced by the Austrian and German Alpine Associations who have a joint cartographic function and they have kept a tight lid on it. You don't get the freely available KML files for display in Google Earth which I have found so useful for planning my itinerary for France and Switzerland.
In terms of time I think the 54 day Wikipedia option will prove the worst case scenario and instead of 2 options (the Alpine and sub-Alpine) I think there are 4.
Firstly there are two variants to the Alpine route. You can knock off (and still be on the E4) some of the most time-consuming and scariest bits of the Alpine route - the less tough Alpine option reduces the time by between 6 and 8 days.
The downside of the unofficial John Hayes variant is that although you always walking on the E4 you have joined the bits up in an "unapproved" way.
What I'm waiting for now is a couple of publications (in German unfortunately) which I'm hoping will give me enough information to decide what to do. I guess the key thing I need to know is which variant will give me the best chance of getting to the Hungarian border in time to complete the last leg of the journey.