Return the board for a refund. The Choc Mini has a poorly implemented debounce that causes chatter. It seems that even adjusting the debounce timing (using Fn+F11 or something?) doesn't solve it.
IMHO, the best weight for linears is 65g/67g or so. I use 62g springs in them, though, since that's my favourite for Clears and I already have a bunch. Red springs are too light, Black springs are too hard. I suspect that Gateron linears with 62g/65g/67g springs would feel REALLY nice (smooth stems, perfect strength spring).