I wondered if anyone had a good guide for grammar as I have finished the tree, but there are still several bits (eg. aby, abyste, some of the stuff covered in the 'skills' topic) that I struggle on, so if anyone has any good links I'd really appreciate it.
We normally recommend http://www.sthi.eu/tl_files/Enclosures/K.Tahal-Grammar.pdf there must be some thread around or some Tips and Notes with some more links.
This book appears to contain even more uncommon features (past conditional and even antepreterite) https://books.google.cz/books?id=huHvHt6hIGoC
Neither of them contains transgressives (they are uncommon, but still more common than the antepreterite).
you could try memrise.com - https://www.memrise.com/course/70302/new-czech-step-by-step/ or if you really want to get into it have a look at have a look at this website - http://www.czechstepbystep.cz/en/index.html
This site helped my now ex girlfriend who is from Russia.