For now his " I only need 1% stake" for attacking nxt is only a claim (a bullshit one imo). Still I would donate him some money if he could pull of an attack on Nxt testnet.
His claim he made was 6.6% to attack NxT, that's why I used it above, not 1%.
Ok, then I need 2x the supply. Or maybe I need 1/30 of that and wait 30 days. So I need 1/15 of the supply. That's 6,6% according to your weight estimate. Not far from the 5% that I mentioned. So again: Not 50%. More like 6%
For now his " I only need 1% stake" for attacking nxt is only a claim (a bullshit one imo). Still I would donate him some money if he could pull of an attack on Nxt testnet.
Btw, is there some proof that he succeeded with apexcoin, or just his words?
Proof:
Bittrex confirmed his APEX attack.
https://bitcointalk.org/index.php?topic=686403.msg10169983#msg10169983