I just got 2 propacks of new Portra 400 and 2 of new Portra 160 and haven't finished and developed a roll from it yet but I've been printing Ektar 100 lately (all 120) and have no problem focusing the Ektar. The grain is small so I usually focus on a sharp edge in the picture instead. At any rate, RA-4 paper is fast enough that I'm usually using f/16 to get the times to something reasonable and at that f-stop the focus isn't as critical anyways.
I'll let you know once I print my first roll of Portra 400. Have some in the Yashicaflex right now but I'm shooting it at 1600 (indoors available light f/3.5 1/50th) so wonder if a two-stop push will give me grain in the dye clouds to focus on? Will see. I'll shoot some at 400 as well, it's a crappy week weather wise, rain, rain, rain, compared to the recent weather where I blew through 2 pro packs of Ektar 100 and managed to overexpose some (Ektar doesn't like overexposure unfortunately, it blocks up pretty bad compared to Portra).