Although I don't give investment advice, my personal strategy is to avoid buying any votes when the market is in decline. The reason for that is that the rewards are paid out based on an internal price of steem that's based on a three day trailing average. So if the market is dropping the votes you're getting are at the live price which means they're lower than they would have been. However, the internal price of Steem is still the average from the three days before, so if the market keeps dropping, you don't get as much in rewards as you would have if the price stayed the same, or if you waited for the price to bottom out. The best time to buy is when the market is headed up. Again, all that is just my opinion, it's not investment advice. You'll want to do your own research. ;)

Ahhh, sorry, I misunderstood your question. The answer is, "No." Once you have selected a payout option, you can not alter it. Therefore, with the price this close to dropping below $1, you have to ask yourself if you think it will drop below $1.00 in the next seven days. If not, stay with 50/50. If you think it will drop below, then do 100% powered up. Make sure that matches with your strategy though. I can't advise you, I can only give my own opinions. ;)