Thoughts on New Family Office?

Was recently pitched to join a startup family office and have a few doubts on whether I have the ability to excel in this environment. Effectively, the family business was sold for USD 300-500mn - debt/alternatives are being outsourced to PWM and the equity portion (in this case USD 75-150mn) will be employed in a concentrated portfolio of 10-15 positions. It would be a family member and I on equity and two seasoned traders managing a book on FX. Anything goes - long/short and no geographic/sector constraints.

I've been in Asset Management for a long-only fund 2.5 years and I'm not sure I have the portfolio management ability at this point quite yet (recently left my role in a fund that managed USD 3-5bn and I'm looking to join a larger institutional manager. Could this be a learning opportunity with the family member (who has an investment background) or possibly an unstable waste of time?

Thoughts?

Associated Resource: WSO Family Office Database