You will have a BLAST in the Birddog! I can't give you any advice, as my few hours in an O-1 (later designation for L-19) were over 30 years ago. I probably had less than 200 hours TT and NO taildragger time when I checked out in the Birddog and a Super Cub at the same time. Both were fun, but I much preferred the Cessna. Much more comfortable for a big guy. Open up the windows, drop some flaps and just float lazily around down low enjoying the scenery. Great for flying out of pastures or off dirt roads out in ranch country. I took one on a few weekend trips of 500 NM out on Saturday and back by Sunday night - NOT ideal for that, but I was building time then anyway, so WTH.
You shouldn't expect any trouble checking out with your Champ time. Have fun!