I've had real good luck using Megabites. Like **SJ** said under studding is more likely to cause damage so that's why I'm leaning towards 168 pattern. I don't want to have to bully the sled around corners so hoping 168 keeps me a little free in the turns.I'm going 4/2.
I have run that pattern on my MCX 290 Apex for 5 years with no issues.
Also ran it on my Supercharged RX 1 for years. No issues.