yeah i know where your coming from. but look i dont own a magna helix. im really not even familiar with them. he told me he had all the equipment. well he didnt have a motor pulley. i recognized this, and am 60% sure it will be an issue. just from past experience. and i've changed pulleys before, i cleaned condensors before.. shoulda coulda woulda etc. the guy that i met off some chat program last night.. that i did this install for 60$ canadian. said he would of been happy to just get the lines ran. right now he has a fully operational a/c unit thats blowing cold air. i gave him the heads up on the condensor. he should clean it cause i told him to. and the pulley well he should get that with the belt too if he wants me to install it. i mean comeon he's a plumber but still he can get these things.. and is smart enough to know what i say should be done. he aint just some HO.
Most of us started our careers without all the tools we need.
Being an oil furnace you could check the heat rise to find out the cfm.
But thats another thing that you'll learn as you go.
He may be a plumber, but you might be suprised how fast you become a %$#% that installed his system if some thing goes wrong.
Just a heads up for ya.
Good luck, and take care.