i think the t20 is more than adequate for any air rifle set up ,i have t20 with doubler on mine its excellent but heavy in fact i think it dont even neeed the doubler ,i got one of uknv kits tubecam off pete , for standing or resting shots they are superb , but i felt walking around the fields & keep lifting the gun scanning its damn hard work ,you deffo need a spotter with them ,but for ratting ,for £120 they are every bit as good as any ns200