Ok,
 it is apparent from the posts that dropping to 5% 2 years early is not currently acceptable.

Zeit has a 20 day min POS rate verses apex's 24hrs , and that may make all of the difference needed to protect zeitcoins from such an attack.

So we can drop this discussion , unless more coins are attacked in the near future.

Would like to recommend that everyone begin spreading their coins so they stake more times per day, as this will have a effect of strengthening our network without making any code changes.
I am going to use coincontrol and set mine to try and stake every hour for 20 days.
If a lot of people do the same , it should block any potential attack.

Thanks everyone for being part of this discussion.
Hopefully it will not be an issue.