As far as I can tell, Doki only ever did 4 episodes of Baka to Test season 2. That was a joint with SGKK. Those weren't on the Doki's packlists but I did find them on
SGKK's packlist. Eps 1-4 of season 2 were the only 480p versions I found as XDCC.
In torrents I found [Mochi]'s 400p .avis of season 1 on
Nyaa with 1 seed and a 480p torrent for [FFFpeep]'s season 2 on
Nyaa with 7 seeds. Nothing was on
BakaBT since the show has been licensed.
It looks like you will have the most luck getting 720p: I found XDCCs of the entire S1 and S2 by other groups at
http://doki.co/releases/xdcc/. Enter "Baka to Test" in the search bar and it brings up the [Mochi] 720p S1s and the [FFFpeeps] 720p S2s. Click on any listing and it gives you the exact /msg
(example: "/msg Ginpachi-Sensei xdcc send #5276" for Baka to Test ep.1) to copy and paste into your IRC client. I did a quick test and it seems like you can send a /msg to Ginpachi-Sensei from any Rizon channel: The Ginpachi-Sensei bot doesn't have to be listed in the users with the other %bots.
One good general packlist to search is
#NEWS where I found even more Baka to Test releases
here. Like the [Ayumi] releases of S2 episodes and specials on Rawrbot you can access in #Doki. A tricky bit is getting the experience to know what channel the assorted bots can be found in. Most bots (like
Cerebrate) require that you send the /msg from a known channel where the bot is located in the %user list. However, a good clue is going to the IRC channel of the group that did the release and looking in the user list there for the bot name.
Good luck.