Nice choice of location!! How did you manage that!
I am not surpised at the larger dish, as I saw one report from someone with a 150 dish in Nuremberg, and they were picking up OK... but you are further N and E, which I think puts you the wrong side of the next dish size.
But like all things until we see 2E operational, all is guess work.
I was born here, it's the misses that comes from the NW of England. We used to live there, but Maggie and Nigel saw to it, that I as a foreigner was not able to get a job after they killed of all the industry (I was working for Leyland engines).
Yes, I seemed to have picked the spot. The first null is only a few miles to the east. I commissioned a company that usually does head stations for hotel and cable providers. Your local satellite guy will be well out of his comfort zone with anything over 1 m. The firm monitore´d 2F for a while and reckoned, that 180 cm should do it. Since they are based about 50 km east of Pottenstein, I ordered a 180 cm with the option of upgrading, should there be a problem. My best move yet. After 4 months and 200 pages of signal protocol I knew, that there is no way of watching without interruption. So I thought, I am not going to put anything over 240 cm in the garden (half of the town thinks I'm nuts anyway) and decided to to it. If that won't work, then that will be it for me.
The dish is a 240 Raven (formerly Andrews) offset. It cannot be mounted on a wall or roof since it weighs just under 200 kg incl. the mount. Because I had planned for 180 cm I made a concrete flag 100 x 100 cm, about 30 cm thick, with a 120 mm steel pipe mounted on top. But since the 240 cm is so heavy, I fixed two steel pipes from the mount onto the garage wall in order to make sure, that the top heavy dish does not keel over. It also stops the dish from oscillating in the wind. But according to the manual the mount shpuld be sunk into the ground at leat underneath the frost border (about 1m to 1.5m) in order to keep steady in storms etc. There is about a ton that pulls on the diah if the wind is strong.
Since you are neare to the main signal beam, you wont probably need a dish that big.
By the way, in the moment I have 795 SQ on CH4 HD - totally abnormal to what I have seen for the last 6 month.