If the UA-5's drain is 450mAh, then you can expect to get roughly 6.5 hours from a fully charged 3000mAh battery (3000/450).
They include a 200mAh charger with the battery, so it takes 15 hours to go from fully drained to fully charged. Any higher capacity 9.6v charger retrofitted with the right plug would charge it faster, but you'd have to be careful not to overcharge/cook the cells. A 400mAh charger would charge the battery in 7.5 hours.
You'd prolly want to pick up 2 3000's, use one while the other is recharging at home/hotel. Then swap for the next day and so forth. Maybe keep your 1600's as spares *just in case*.