Now the problem is how to be able to invest when the coin is cheap.
No, forget about that. You told that you are already nearly fully invested. Keep the rest as a cushion.
Planning how practically to execute the sale of the bitcoins is also important. You cannot suddenly repatriate millions of dollars to your bank for example (the limit of "suspicious activity" may be much smaller such as $5k!).
I just posted a thread asking about this: I'm a very small owner of BTC, but when it is worth a lot I'll want to have some cash. What are the best countries to receive the money from exchanges?
Would withdrawing $1000 or so per day not be considered "suspicious activity" as well? I fear that even the smallest amount could be heavily taxed...