Welcome to the site. SRO generally means just that, "standing room only", so I don't think you'll be able to get a seat/table. There's usually enough room in the park so you won't be staring at people's heads, but I've never been up there so I dont know what the deal is with the RF roof. At 1 pm the sun is typically at its highest point in the sky, and it gets to be a problem in RF later on in the day. I'd bring sun glasses just to be safe, but I don't think it should hinder your enjoyment of the game. If I recall it usually gets bad in RF mid-summer around 7 pm, so I think you're safe.
Again, welcome to the site.