canjar set trigger instructions

In some recent purchases I acquired a canjar set trigger for a p14. No instructions though
As I cant seem to finish anything with too many projects on the go I dropped what I was playing with and finally tried it on my model E 303.
Some of it was pretty self explanatory as to replacing the spring on the front with the plug supplied and then doing up the allen screw to take up the slack.
This is when it tips over. The bolt head wouldn't go all the forward.
I did find a little piece of copper shim that I presumed would go under the back of it to sort of wedge it all in place but even that's a bit naff.
I have tried the easy way no I have to call out for assistance with instructions. I had a bit of a look online and some instructions have a brief comment about fitting but it isn't enough.
Was hoping it might be a simple enough to try out and put back to standard if I didn't like it.
anyone help?

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