I have coarse hair around my chin area, and am prone to razor bumps around there if I let my technique slide. I'd agree with the suggestion to go 2x WTG for now - you won't get very close in that area, but you need to get your technique right before you try to get that area totally smooth. Otherwise, good lather and short, but not too slow, strokes with no pressure other than the weight of the razor, treating the chin as a series of angles or facets from below your bottom lip to the top of your neck, thereby avoiding shaving around the curve in just one or two strokes, is important. Once you can do this every time you shave without razor bumps or irritation, you could add a third pass which would be across the grain (XTG), again using short strokes with no pressure.