I am going on my first phesant hunt this weekend in Eastern Mo. One of the guys that is going with us told me go get some 7 or 7.5 and us improved cylinder. Or he said if I am going to use a modified get some 8s. Is this about right and is one better than the other? I just don`t have much experience in all this.

Thanks

I'd take #6's at the very least! I like #5's myself. I use a load called "Golden Pheasant" It's made by Fiocchi and it's loaded at 1 3/8 oz with nickel plated lead shot in 12 gauge. Either choke is fine but, take both with you.
I don't know if you're hunting wild or farm birds. For late season wild birds the Modified choke with #5's or even #4's might be best. For farm birds the Improved Cylinder with #6's or #5's might be best.

I'm a modified man myself, and #5's are my choice of lead for thunder chickens.

Sometimes I have a hard time finding them so stick a #6 in barrel and #4's behind that

I do just fine with a #7. I think they work great!

Since you are evidently going to a licensed preserve or club, you can use 7 1/2 shot with modified or full choke(what I use). You'll be much closer to released birds than wild birds when they flush. Heavier loads on them often means no meat left to put on the table.