Yes, CPQ. I assume you have well funded equips, so you should Slash Blast the crap out of Rooms 3-4 from early 30s til 40 or so, asking for summons whenever possible, then mix it up until 50 with some Rooms 5-6 Rombot pwning and finding friends/TW groups to summon for you in Rooms 3-4.
IIRC, you're making a spearman. What are you getting after Mastery, HB or FA? If FA, Rombotting will be better than with no FA, though still not as good as mass summons. FA reduces mass summon killing speed slightly. But you'll still get 1k+ CP, which is way more than enough to get good EXP. (From experience with my page, who has max FA.)
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