In my opinion I think Capital World G/I is a solid performer and should be the core of your portfolio. If you just want to put your money in every month and forget about it the go with 100% CWGIX. However if you want to keep an eye on it and re-alocate it every so often I would add a few funds to that.

50% in CWGIX (capital world g/i)

25% in SMCWX (small cap world fund) which in my opinion, the Small cap companies have been hit the hardest and is a good time to get in. With time on your side the small cap U.S. companies have average over 14% where as large cap have average 9.6% during the last 80 years or so.

25% in  NEWFX (new world fund), this fund has great since its inception and can compliment your CWGIX core holding

American Funds has a great management style and we always use them as the core holding if not all the holdings in portfolios. There are other funds that have performed better in the small cap and world funds but not sure if they are open.

Best of luck to ya,

Chris