Very interesting. I am much to the north from you, but I did notice an SNR increase as of 21.30 GMT. I have been noticing the cycle of signal variation from 2E is different from 2F. I think that (in West Iberia at least) SNR from 2E peaks around 22.00 GMT. Give it a try tomorrow at same time.
The best transponders for me seem to be is 10891H and 10773H. What is your LNB?
I'm not sure Obidos is in a null, not a deep null at least. I would guess you're on the fast drop-off zone. And if so, the slightest satellite wobble could be noticed by you.