Quick question - have two of these, arrived today and am hoping to use them as night nappies. dd is nearly 18months, 22.5lbs. When the nappy is fully boosted there is considerable daylight between her bum cheeks and the leg elastic. Tightening the velcro gives red marks. All I can think of trying is poppering down one setting, is there anything else I could do? I'd love to get this nappy fitting right. Thanks.