Everything you have on whatever exchange that is on is all pure profit now, correct?
What I would do is spread a column of buy offers downwards as well as a column of sell offers upwards, to profit on the ups and on the downs, basically acting like a market-maker.
If you like the long (long, long, generational even maybe) prospects, build the buy offers column all the way to lowest price the exchange allows you to type in and hope some whale gets hacked and all their coins dumped dumping the price way the heck down, oodles and oodles for you cheaper and cheaper and cheaper, your "family office" in generations to come could be a whale in this, etc...
Once you are where everything you have on any exchanges is all pure profit, you need be scared less than offline people about leaving stuff on exchanges.
I had way more exchanges fly by night, "get hacked" etc etc etc than seems to happen recently yet still came out way way ahead, the fly by nights just another "cost of doing business", oodles of profit regardless. Being there with your offers already in place is big advantage over people who have for example to notice a coin change sneaking a look in coffee break at work then have to wait to get home to fire up their node then wait for node to catch up to blockchain then wait X number of confirmations for exchange to acknowlege arrival of coins by which time any peaks or troughs are smoothed out by people positioned to react faster.
-MarkM-
EDIT: Any time you enter another exchange, work toward everything left on that exchange being pure profit... Probably entering with pure profits from previous exchange(s).