Disclaimer: I may have just had 4 off rims, other have not had the issues I had.
My 2 cents with the BCI chasers, mine were 17 x 8, is to ensure the tyre is mounted correctly IRT the valve stem.
Also esure your fitter uses the correct attachment method, we tried both back cone and pin plate, and placement points for the weights, mine ended up with them everywhere.
In the end, after 2 tyre shops (both of which I have used for years) and 3 goes at fitting and balancing there was quite a bit of lead added to quell most of the shimmy at around 95kph, but at about 135kph the shimmy got pretty bad again.
I've gone back to stock VX SS rims with the same tyres and have no issues.
The same tyres on stock rims balanced fine with minimal added weight.
BCI did help me out with the correct balancing technique and was willing to replace the rims though, I just couldn't be bothered and was "over" the whole thing and didn't have the time or inclination to post them back from my location in Sydney to Vic.
Our view was maybe the jig or press was a bit out during the construction of the rims, maybe.
I ended up giving them to a mate for his trailer.