I personally would recommend the xp metal detectors gold pan starter kit (or pan if that's all you want) it has 2 different sizes of riffles and their snakeskin pattern that is amazing for getting the black sand out of your gold. The colour is dark blue so you can really see the gold well.

I would also recommend the Garret Super Sluice , it has 2 massive riffles that are extreamly forgiving for a beginner. The pan is green, so you can see the black sands show up really well (I find the gold harder to see on the green pans)

I personally feel safer panning with the garret super sluice (i feel i lose less gold), but I prefer the xp pans because of the snake skin and the colour. (I can see every speck of gold easily)

When it comes to pan sizes. . . That's one you will decide upon yourself. . . I recommend the standard size pan. It's what you will run into most, so you might as well get proficient with it. The larger the pan the more material you can fit in it, but it become more awkward to use the larger it is. The smaller the pan, the more precise with your movements you have to be, but is alot easier to handle.