Since my link reference probably was confusing, here is the article. By the way, bchatt, your solution looks like Desmo_Demon's first solution, that didn't hold up for long. Keep an eye on it.Here are a couple of pics. Please bear in mind I fashioned this solution by hand , in a hurry because I wanted to go for a ride (as always!). You can see the new black OEM keeper plate against the sprocket, then 3 washers which space my additional plate to just flush with the end of the countershaft. The most important bit is not visible - the central boss which allows tightening the M8 bolt, while allowing the sprocket to move around - rotational slop as Bryanc123 puts it, is not impeded or transferred to the additional keeper plate. It seems to be working fine. I needed to put a washer under each of the 2 plastic cover boltholes to prevent the M8 bolt head wearing on the inside of the cover.
And, no Tonered, I didn't put longer retainer bolts in, but I looked long and hard at the originals and I sure would have put some longer ones in if I'd had some, but, well, you know, the twisty roads were calling me
See the copy of magazine article written (page 19) by him detailing the whole idea of using a sprocket to work around a buggered up countershaft spline.