Unfortunately, Hide does not work on him after you have engaged him. However, you can use Hide at the start to ensure your SA hits. My first run I didn't line up properly b/c he has that weird stance. 2nd run popped Hide at beginning to make sure I didn't do that again, and won that time around. Pretty much same strategy as already posted, slept TP to 150% (for more Accuracy, since higher TP is higher WS accuracy), SA, DE, Ic wing, DE again. This took him to about 50% or so. Maat promptly used PD at this point so I Flee'd back to entrance and popped a few potions. Popped my PD once he caught up with me, and then it was just stay alive till I got enough TP for another DE. I did not use a blink band at all, but went in with capped evasion and a ton of eva+ gear. It paid off cause his Asuran Fists missed. Used squid sushi as food, since it has DEX mod for SA/DE and AGI mod for some small evasion boost.
As for skillchain, regardless of whether you stack SADE or split, it will not affect Detonation damage. Level 1 Skillchain damage is determined by the CLOSING weaponskill, not any other factor (other than the usual elemental resists), up to 50% of damage from that weaponskill. Since you can't close with a SADE in this case, it won't make a difference. Personally, I found splitting to be more effective for the spike damage for this fight.