You should try Mangy-Tailed Marvin as SCH/RDM and see how low you can get your time, it's a lot of fun. My 1st kill took 40min, best so far is 10min with meds/boosts/2hr/earthday. Can also do Brooder (Serpentes), Chasmic Hornet, Piasa, Keesha, and others.
You can also solo t3 VNM Ruminator, hardest part is the pull. It's doable with a well-timed Hermes Quencher (to escape canyons) and good knowledge of the terrain; mobs path weird in lots of places between confluxes 2 & 3, so you can gain distance here and there on the way to the pin. Aspir works, so it's really just a race to see how fast you can kill it (like all pins, really); AoE attacks are damaging, but as long as you wear a standard idle set it's nothing a Drain won't fix. Also, make sure you keep barspells up in case it decides to steal your buffs; dispelling your Sublimation off a monster is never fun.
RDM can attain an almost static 50% reduction to recast time, SCH can over shoot this for a total of 60% reduction under Alacrity (provided you are wearing loafers and keeping dark weather on yourself)
MACC is a joke, any job with access to mage gear can hit close the MACC cap on legion mobs, which is why my BRD/RDM can land slow/para/blind despite having only 150 skill (from /RDM.)