spring stays 2-2,5mm above the axis even if it gets totally pressed. The fuse adds 3mm so the total length stays the same buddy. But as you said you have to be a little more careful when you screw the telescope with the fuse not to squezze the battery
Sorry my mistake. But with the spring it can be depressed but not with the fuse kit. So got to be more careful not to tighten it too much..