First of all, the Aggressive portfolio is modeled for someone just like you.  Let's say you have $50,000 to invest instead of the $200,000 we started with.  You would simply divide by 20 to get the amount to invest per slot, which in this case is $2500/slot.  In addition, with the 2007 ROI, you would have about $60,000, or 24 slots now.

One caveat, the lower you go in principle, the more commissions are going to impact your ROI.  If you are lower than $100,000, you will want to consider one of the super deep discount brokers like thinkorswim.com -or- possibly even one of the free trading offerings like Bank of America or Zecco. 

I would move my portfolio to Schwab ASAP though as the toolsets allow you to do many more of the things we alert to, like hedges, options, etc.