i'm building a shop at my house made of concrete block. before i put the roof on, i would like to install a hoist system to lift things like car engines, metal lathes, etc... my shop is 20' x 30'. i would like to place 2 "I" beams on top of the block from one 30' wall to the other, thus spanning a distance of 20'. these 2 "I" beams would each be placed 5' out from the center line of the 30' walls. in other words, the 2 "I" beams would be 10' apart. one beam 10' from the front of the building, and one beam 10' from the back. i'm planning on using trollies to hang another beam perpendicular and below these 2 main beams from which to hang a hoist on another trolly. i need this system to safely lift 1200 to 1500 lbs with minimal deflection. i probably won't ever lift over 600 lbs, but i want to make sure it's strong enough for any situation that i may create for myself. i understand that deflection is inevitable, but i would like there to be a little as possible. so, my main question is, what is the smallest beam i can use for the 2 main beams? i was thinking that a S8 x 18.4 or a S8 x 23 would be sufficent, but i need a second opinion from someone that is a math wizard. thanks in advance.