there is no best cross. by doing one or two crosses all the time you can learn what pieces your looking for very well, and improve your look ahead. but by being color neutral, that look ahead and recognition of pieces will take a bit more time to develop. with CN, you do open yourself up to more 'lucky' or easy cases because you have more options. Example; if you where dual color with green and blue, and there was a 1 move orange cross, then you would pass it up, with color neutral then you would take it.