Starting Pyre, buy her a book on day 1 and go as far from the castle as possible.
With the second wave (demons and pits) near the castle, clear out what's under guard, and with the third wave (ifrites), finish off another direction; usually devils are placed on 117, sometimes earlier if gogs are there from the start. Devils are placed in 33% of cases on day 1.... well, who could then withstand a rush against Inferno on day 2? ;)
Actually, I really did place devils on day 1, on sm in TE (where gold scrolls are replaced and there are crypts on lava). And in SoD it's certainly fun. 20+ mercury is definitely brutal. And even then, if you have that kind of money, it might be better to build the castle and do a full buy-out on 121, but one still wants to place devils, no doubt!