I'm using the Breville Bambino Plus. Stock protifilter with the plastic piece taken out. I was advised to use the 16-20g basket to avoid any issues with basket height clearance. I have no issues with height clearance. It's just a tight fit in the portifilter, but it works (using stock spring so maybe thats why?). I'm using 18-19g doses (mostly closer to 19g). I found with anything less, there was higher likelihood of the pucks not coming out clean, but could be our beans (namely medium / light roasts at this moment).
Highly recommend for anyone wanting to make a relatively simple and affordable upgrade! Nothing wrong with the stock baskets (used the single walled double shot), but with this IMS basket I can grind finer with less bitterness with the default programmed double shot.
I had a few questions for the Coffee Addicts staff and they responded very quickly and were very helpful with making my decision to buy this! Got the product timely and had no issues.