Hi there. I use webiress through comsec which has an excel add on that allows me to pull the real time data including the match price for a given stock into excel.
From there I calculate the market cap change for the XTO twenty stocks. Its not quite the XJO but pretty close. Manually typing in and updating shares on issue for 200 stocks wasn't on my thing to do with my life list :-)
Essentially I use the match price multiplied by shares on issue to give the market cap and scale it to match the XJO.
At the moment I am seeing 4748 so the gap is closing downward to the SPI 4744 level.