I'm so happy today as I've just fitted my new titanium 2g (6mm) x 5/8" (16mm) ID BCR (CBR) to my PA. I've been on a mission to safely stretch up by use of weight rather than tapering. It's been an interesting project to hit my 2g target and I've learned alot about using this technique by periods of increased weight then reducing it and repeating the process until the heavier weight feels comfortable to wear all the time. At this point I started testing the next gauge up to see how far off mark I was and then replace the heavier weighted jewellery until the next gauge slipped in naturally without force.
I have collected a number of different style and sized balls to fit which provide range of weights. Fine tuning can be made by attaching other BCR's. Titanium jewellery is lightest and I always use it through the piercing itself but make adjustments to the ring with my heavy duty opening and closing pliers (essential tools) to allow me to fit steel balls which are heavier. As the gauges have gone up I've personally found the stretching time shorter and this last stretch has taken 3 months. Here is a pic of the jewellery I ultimately used to go from 4g (5mm) to 2g (6mm). It has a 3/4" (19mm) 316LVM stainless steel ball and was custom made for me. Trust me when I say you will need serious support underwear if you exercise or run!

It may not be as fast as using a taper but it is immensely satisfying when you listen to your body and it adjusts all by itself.