Mighty Mouse
It's All In The Reflexes!
There is that fine line to tighten and not over tighten. Mine split about 6 months also. Like you I bought newer spacers that are a little shorter. They have held up for about a year and a half. I check every time I ride. I may get a tad more wind due to the shorter spacers but they have held up relatively well. At high speeds over 90+ I get hammered by the wind to my head but cruising at 80 to 85 not too bad. 
