stu....have you thought about just using a battery spacer? I found on one of my mods that my IMR high drain 18650 was too short for the spring but I took a very small magnet, (actually a replacement door magnet from another mod) put it onto the positive terminal of the battery and Viola!!!!!! there is a 2mm difference in safe chemistry batteries compared to protected li-ion batteries. Even though both are 18650's both should be 18mm in diameter, both should be 65mm in length, I found the PCB on the Li-Ion is about 2mm.
Hope that helps!!!
BTW....where abouts in MB are you? I just moved back to NY from MB last year, I was living on 67th Ave N between kings Highway and 17. Loved the area and the weather but missed the family up here.