I would use the asym drilling guide.  The stuff from that series (and the Raid) are weaker asyms, but they are still asyms.  If ebonite doesn't have a sheet for that core, you may benefit from looking for a company that has similar core stats for a line of balls and using their sheet.  The "key" sheet, and the centrex symmetrical mass bias are both stronger asyms so they may, or may not translate to the SR series.
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four fried chickens and a coke[/size=4]

Let me say something, let me say something...
AAAAAAAAAAAAAHHHHHHHHHHHHHHHHH

It's on the low side, but you can still fine tune your reaction with it! I drilled both the SR300 and the RXS300 the same. I bought both of these nib and for me I drew a line from the pin thru cg to the mass bias. I then place my 1/4 scale on that line and mark 3" over and mark that location and draw a line from that point up and the pin is 1/2" right of that line. The ball gets down the lane easy and for me the ball reads the midlane better and has a nice strong arc move on the backend. I shot 300-266-258= 824 in league two weeks ago the first time using it and the RXS300 gives me the same read only it's has a stronger move at the backend. When the SR300 is too much ball, I go to the RXS300 and don't miss a beat! I like the pin below the fingers on the higher rg ball to get it to read the lanes quicker and not jump off the back of the lanes at the backends. Good luck to you, Bruce
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"Train a child up in the way he should go and when he is old he will "BOWL TO WIN" and not turn from it."