What do people recommend for determining the nuances of asset allocation, beyond the first tier of Equity-Bond-Alternatives. For example, picking what percentage to have in large/mid/small cap and international developed and emerging markets - it all seems fairly arbitrary to me. And then Personal Capital goes even detailed into Value and Growth, and I don't really know what to determine my asset allocation should be. It'd be helpful to find a resource that guides you in picking that level of allocation.
FWIW, right now I've been aiming at 60% US stock, 30% International, 8.5% Alternative and 1.5% bonds. For the 30% international, I split it 20% developed and 10% emerging markets. For the 60% of US stocks, I split it into 30% large cap, 18% mid cap, and 12% small cap. I'm not religious in keeping to those splits, but it's generally what I aim for if something is getting too out of whack. Using Personal Capital's asset allocation tool, I generally aim to keep Value-Core-Growth fairly even .
Context: I'm married, 33 years-old, no children. Total dual income $116,000. Net worth $259,000 (approximately $69,000 in cash, which I am reducing by DCAing into investments).