Boyer sell a few systems to suit points in a can, and the basic system doesnt cost much more than GBP 80- from Motobins.It will work with your existing coil, the hall sensor in a can may not.
Their latest system, the Micro power is also available and comes complete with a high power miniature coil, and it probably costs less than the hall sensor system and a decent matching coil.
I have had a Boyer microdigital on my /7 for well over ten years, and a micro power on my twin plug G/S for three.
They have been fit and forget items, and they made a noticeable improvement to performance too - the curve on the twin plug version is excellent - well at least it is compared to retarding the stock unit 2/3 degrees.
But then they were fitted because I wasn't happy with the way the existing system was working so that was to be expected - if you are happy with the way your existing system works just follow Stephens advice and fit the booster.
Adelaide, Oz. 77 R75/7. 86 R80 G/S PD, 93 R100 GS, 70 BSA B44 VS ,BMW F650 Classic