Starting conditions: Poland and Austria and I (BB) rivaled Bohemia. Poland Rivaled Teutons, as did I. Reclaim Neumark, take the 2 Bohemian provinces to the north, take one Silesian province, and free Silesia. For some reason everyone hated Austria right around 1455, and their king died, making me Emperor. This basically doubled my force limit, and tripled my manpower. Inherit burgundy (Brabrant was free, though). I took more land, beat a coalition, vassalized Cleves and Bavaria (Bavaria was a 1 province Inglostadt, freed by demanding unlawful territory from Salzburg - diplovassal, actually). The netherlands revolted and nearly lost their war for independance against the brits. They had 1 province left, and I diplovassalized them, knowing that they would grow quickly, since other low countries would join them.
I converted to Protestant because I managed to get a CoR from Denmark in Holstein. I had planned to stay Catholic, but the Reformation was insanely strong, and I'd basically only be taking blue provinces for the rest of the run, probably destabilizing me, since I took religious. Easily won the league war against a Portugese empire, got Emperor title back. White peaced a coalition. Took more land.
It was 1610 and I needed 7 provinces. 2 were owned by my ally France, 2 by Bremen, and 3 by Lorraine, Mainz, and Nuremburg. The latter 4 were all truced by me due to coalition stuff, so I trucebroke and took the 4 provinces. I didn't have diplo ideas, so this hurt REALLY BADLY. Lost my alliance with France because I needed her provinces, picked up Ottomans and Hungary as my friends. 1624 and I win a war on France for Elsass and Sungdau. The one real scare of the campaign was in 1633, when literally all of Europe (except Hungary, Ottos, and Russia) declared war on me for coalition. Luckily, by this time, the Netherlands was large enough to be a 100% warscore concession, and I gave up my overlordship of them. They were an elector, so it hurt a bit.
From there it was smooth sailing to 1646, when I finally got enough Paper Mana to get tech 20. The reason I don't have Religious ideas anymore is because I refunded them (I only had 2 policies, though) for the Admin points, since I had a 0/2/3 king. Changed to Reformed because the Emperor can't form Germany, and changing to reformed lost me the emperor title.
I'm relatively sure that you can't really form Germany before 1642, since before that the technology will cost more than 999 ADM, even with 2 ADM idea trees fully filled out.