Drop in Build questions

I just built a drop in as practice for making a my perfect EDC Surefire 6p set up that is throw oriented. I am using a 2600 Mah 18650 battery and I used this driver and emitter:
8* AMC7135 4-Group 2~5 Modes LED Flashlight Driver Circuit (Nanjg 105c)
Cree XP-L HI V4-1A 455LM 6500K LED Emitter

Putting it together was easy. Making it work well is hard! Here are a few issues I am addressing and I would appreciate any coaching I can get.
1. It had excellent throw and a good concentrated beam when I first assembled and tested it. I took it apart a few times to tinker with the reflector and insulator, and now it is wayyyy less powerful. I tried a battery with 3400 Mah, but that makes no difference. Could a poor solder joint cause this?

2. The tail spring on the driver is very short so the battery can slide back and forth. I used a tinfoil pad on the tail switch/battery end, and I slipped another spring on the driver spring to lengthen it. Would this cause noticeable resistance and rob my led of power? There isn't much room to solder a longer spring on the driver, but I might have to do this.

3. I used this, Thermal Silicone Grease Heat-Sink Compound, to glue the emitter to the pill. It isn't a glue I have come to realize. Can I clean it off and just use epoxy to hold the emitter in place? Would epoxy work as a potting to secure the emitter and soldered joints in place? Does epoxy act as an insulator that will prevent the reflector from shorting out the led?

When I get this dialed in, I plan to build a drop in using this combo:
QLITE REV.A 7135*8 3.04A LED DRIVER - 17mm
$6.49
CREE XP-L V6 1A LED on Noctigon 16mm MCPCB

I have been lurking here for a while and that's what gave me the courage to try this. Thanks for any advice.

Might want to see if this can be moved to the modification section of the forum. Go check it out, there may be something that can help over there. I have been getting some Malkoff and P60 hosts to start modifying those myself to practice for modifying my Leupold. Good luck

Oh yeah, welcome to the forum!

Did you heat sink the drop-in properly by wrapping the module so it fits snug in the host? You need to transfer the heat from module to the body. Also, magnets (on the negative side of the battery) work well to take up contact gaps.

I did wrap the drop in for a very tight fit and that doesn't change anything. The magnet on the battery is a great tip! I will do that as soon as I get home.

Update:

I de-soldered the leads to the LED star, cleaned them up, and re-soldered them to the star, and then I made a better insulator to go over the LED. The drop in works perfectly now and has excellent throw and a good, clean beam. Thanks for the support.