The spell you cast doesn't need to be among the cards milled with Saruman's trigger, so you can set things up with mill spells like Ruin Crab and Mesmeric Orb
I have yet to play with this card (and red is quite restricted in its ability to get lands into the graveyard)
The terminology we use at Magic for the two main approaches are top-down or bottom-up design. Top-down starts from a creative angle

Alchemy: Ixalan Card Image Gallery WHITE | BLUE | BLACK | RED | GREEN MULTICOLORED | ALL CARDS SPELLBOOKS | CONJURED CARDS WHITE Cogwork Progenitor Legion's Chant Radiant Smite Valiant Batrider BLUE Herald's Reveille Hymn to the Ages Landlore Navigator Plunderer's Prize BLACK Chitinous Crawler Dusk's Landing Legion Reconsecrator Mycelic Ballad Phantasmal Extraction RED Caldera Breaker Kamachal, Ship's Mascot Pirate's Landing Ribald Shanty GREEN Colossal Chorus Mythweaver Poq Propagator Primordium Scalespeaker Shepherd Wingbane Vantasaur MULTICOLORED Brazen Boarding High Marshal Arguel Merfolk Tunnel-Guide Mycoid Resurrection Reflection Net Scalesoul Gnome Stalwart Speartail Tan Jolom, the Worldwalker Spellbooks Brazen Boarding Admiral Beckett Brass Corsair Captain Spyglass Siren Staunch Crewmate Scalespeaker Shepherd Ancient Imperiosaur Burning Sun's Avatar Carnage Tyrant Charging Monstrosaur Etali, Primal Conqueror // Etali, Primal Sickness Ghalta, Primal Hunger Gishath, Sun's Avatar Quartzwood Crasher Regisaur Alpha Ripjaw Raptor Shifting Ceratops Territorial Allosaurus Tranquil Frillback Verdant Sun's Avatar Zacama, Primal Calamity Conjured Cards Colossal Chorus Caldera Breaker Volcanic Geyser Wingbane Vantasaur Savage Stomp Naturalize High Marshal Arguel Arguel's Blood Fast

15 cards per pack
if you wanted to buy them now, youre looking at roughly $6868