Specific Question for Crawl

[getter77]

I'd say don't let casters onscreen unless that means around a corner or somewhere else in easy reach,  throw down big time with Summons, especially summon small mammals and the like, then once you've got some strong/varied squads you can bring to the fray when needed make extensive use of Sif Muna for books to learn other spells to complement the Summons.

[Dedastary]

Don't tackle orc wizards and priest without mephitic cloud with caster or without some other way to confuse them (unless you allready have a powerfull spell). Specially not wizards becouse even if you have powerfull wand you could miss and get slowed which is really dangerous. You can learn mephitic cloud on level 3 with deep elf wizard or lvl 4 with demonspawn wizard for example. After you confuse them just spam mammels and thats it. And allways have a planed escape route if something goes wrong. Corridor + summon mammels = escape (most of the times).