Hello,
I grew up in LA. Come back to visit family. I grew up wearing Penny's tight neck heavy T's, but have not seen any for many years. After searching over the years every time I come down here with no luck, someone pointed me to swap meets.
Found Shaka and Pro 5 club the best and only worth considering. After examining both thoroughly, it appears to me that Shaka is slightly brighter white than Pro 5. Examine both side by side in various lights and see the little difference. For me, I like them as bright as possible and it is the deciding factor. Both are great and Pro has more choices of colors as has been mentioned.
For all you young guys, these type of T's are not new. We wore something very similar made by towncraft (pennies) in the 60's. Levis, good T's, pendletons and black sandals were it.
Olskool