Radiator overflow questions, advice, pics.. help

[dropanddrag71]

I just installed a new radiator in my 70 c 20 with a 350. The truck has a very bad and damaged universal plastic overflow that i need to replace. I see nice stainless steel ones on the internet but i have a few concerns.
First, what size should i buy, i see them rated in ounces. Next, can i see what your running and where you installed it, Pics, pics, and more pics!! I'd like to see some ideas!! Under the hood is nice and clean, but by no means a show stopper!!! Truck is driven alot in the Florida Heat.