You Are Geared Up. Way to go and congrats on the LCD2's and 2 more sets of T50RPs!
No, I have not tried making holes in the stiffened craft felt when modding "Naked Drivers" (when the stock white driver damping material has been removed from the back of the drivers). Actually, I went the other way. Naked Drivers are too under-damped so bass is excessive, out of control, and so bloated it messes up the mids and covers up the treble frequencies. I posted the "Naked Driver" config, with graphs, that worked best for me in
Post # 244 of this thread. I had to use two layers of stiffened craft felt without any holes to make the drivers behave. This mod configuration measures and performs very close to DBV #3. Here's the configuration:
1. 2 layers of Michael's Craft Store stiffened craft felt, each measuring 45x52x1.5mm, notched for clearance of all 8 driver mounting screw heads, stacked, and secured with 3M Removable double-sided craft felt.
2. 20x25 rectangular thin card stock treble reflector centered over the back of the driver and secured under the stiffened craft felt with thin strips of 3M double-sided tape.
3. 1x7x7.5 cm compressed J&M fiberglass = 1.3 grams.
4. 1.5x7x7.5 cm Rite Aid Natural Absorbent Cotton = 1.4 grams, under the fiberglass. As a substitute, use "Prepared" layers of Rite Aid First Aid Rolled Cotton 2x7x7.5 cm = 1.8 grams OR 4 to 6 Rite Aid First Aid cotton balls as described near the bottom in Post #1 of this thread.
5. Acoustipack Lite (or Paxmate or Silverstone) 2x7 cm trimmed to fit the side cup floor "wells."
6. Newplast (or non-drying plasticine) flush loaded baffle compartments = 9 grams of Newplast.
7. Stock cup vent felt intact.
8. Stock Open baffle ports.
9. Shure 840 pads.
It's interesting that going the other way is working for you. Just goes to show "There are many paths leading to the same destination."
Your measurement kit will be very helpful for dialing-in your mod config. I built an improved phantom power supply designed by solderdude. He posted his schematic at
this link, if interested. Scroll down to Reply # 101. BTW, solderdude is an E.E. and designed the
hybrid tube amps Jeremy builds and offers in kit form; they are impressive and inexpensive. You can also check out all the other cool DIY headphone related DIY projects solderdude designed and shared. Really quite an amazing body of work freely shared with the community!
Hope this helps.