You could bent the rf shielding, so you have some more space to insert the card easily.
I know the problem you are facing, because I have Two A1200 with a Blizzard 1260 and 1230. It gives even more problemen when you try to insert with SCSI-kit. In my third A1200 with a GVP 1208 memory card was inserting this card easily. GVP has made a round spacing and the end of the card. It gives same more room to push the card in the A1200.
http://www.amiga-hardware.com/showhardware.cgi?HARDID=1184
