Yeah, it’s usually better to go D->Lair, clear Lair->clear Orc->then rest of D down to 15. D12-15 can spawn stuff that’s nastier than what you’d find in Lair or Orc. The return is better too: L5 ending and Orc 2 shops should give more than what you’d find on the floor D12-15.
Spells: with Cj, you have all the guns you need for a long time. Prism to kill and block LOS. IMB to get stuff off of ya to run. And by now, you’ve got Spellcasting, Conj and some Alchem and Transloc.
So, what do you need? Crowd control, something to get you started towards your end game goal, and more escapes. What fits the bill?
Apport allows you to grab stuff without getting closer to sleeping bad guys. This should be free with your IMB investment.
Spammals are cheap and can get you that 1 space to escape in a corridor. It’s really cheap to get online. You might even be able to cast it w/ no Summoning even. Perfect stepping stone if you wanna go the Summoner route too.
Blink. More escape, also nearly free with IMB investment.
Meph. CC that’s useful even down to Zot. Cheap too, with the Prism investment. Maybe just 3-4 Air.
Swiftness. Another escape option. It should come online for free if you buy Meph.
Passwall. Now this one takes some thought. It’s really stronk if you know how to use it: i.e., lure stuff into a dead end and pass to leave them “stuck” there (don’t use this if they are too close, ofc). The problem is that it requires Earth, which overlaps with nothing you’ve bought so far. That said, if you are planning to go with LRD, BVC or Bombard, it’s a perfect stepping stone.
From 4 on, a spell takes more dedication. Sometimes you should pass on a juicy one just because it’ll divert too much xp into the “wrong direction.” That’s a game by game decision. But the ones I usually consider are:
Ignite + OTR/Bog
BVC
Freezing Cloud
Yara
Irradiate
Summon Forest or Viper
Death Channel
Permafrost
Plasma
Starburst
Cactus
all of the level 7 ones except Manifold
Which one of the above depends on what I find. But I pick ones that have a common progression: e.g., LRD. BVC, Bombard, or the Summons, or Ice Cloud, Permafrost, OTR, etc. etc. For non-Sif, non-Veh, non-Kiku, non-Goz, I’ll often make this choice after I see what O2 shops give me.
Picking your spell set/progression is a fundamental skill needed by every non-Dj caster. That’s why I usually recommend that a new player watch out for this learning gap if they start with a Dj caster.
Good luck!