Just a thought if you are going to order from Manafont for $8 bucks more you can get this host and have a place for your spare drop in and batteries. I own 4 of them and they work good and are very similar to your Surefire.
Also the KD-C8 puts out a ton of light for $25 bucks, it would be perfect for farm use very floody bright beam. I own one and can say this is a must have budget light if you own 18650 batteries.