I have been working on installing the rings into my 3.1TL's. I took all the drivers out along with the PR and drilled the holes using the guide rings supplied by Larry. Everything worked out well per Raife's directions.
Everything worked out well until I tried to insert the rings into the newly drilled holes that is. I started with the 12" PR ring and went to install it; the first half seemed to line up and go in fine, the second half near the edge of the cabinet I found is blocked by the triangular shaped wood blocks glued to the cabinet back and wall. I found I had 2 choices.
1) Pry up the block and re-glue it to a different position away from the edge of the ring
2) cut away a portion of the triangular block to allow the ring to pass and be flush with the front of the cabinet.
I ended up using both methods, one in the future (more on that in a bit) and in the case of the PR I cut away a portion of the block to allow the ring to pass it. I found it easier to cut aportion away of the smaller triangular shaped block on the bottom of the cabinet than it was to pry it up and move it. The block on the bottom was just too well glued into position to move. The block on the side and back I found I could pry it off and re-glue it to another, further away from where the ring enters the newly drilled holes. I successfully got the ring into position for the PR.
Next I started the 5 drivers (4 6503's and 1 6511). I tried to get the ring into position, but found the crossboards on 2 of the 6503 driver's were in the way of the rings. I had to cut a small portion of it away to get the ring passed it. I successfully got it passed it, but the screw holes on the ring I could not get lined up with the drilled holes in the cabinet. I found out that the rings for the 4 6503 drivers are about 1/8" too big on the outside portion of the ring where it meets the right side of the cabinet, on the left speaker and the left side of the cabinet on the right speaker. I used a hack saw to cut about 1/8" off a portion of the ring directly in between the 2 screw holes on the ring. After trying this with one ring I successfully got the ring into position on the very bottom 6503 driver. I began cutting another ring (1/8") and tried to get it into position in the second from the bottom 6503 driver position. Unfortunately, as mentioned abover there was a wooden crossbeam (that goes along the side of the cabinet between the front and back portions of the cabinet, below the driver hole) that got in the way of the ring. There is also a triangular shaped block (as mentioned before) that was in the way above the driver hole. I have yet to try to pry up or cut the triangular shaped block and still need to get the ring into that second hole.
The third driver hole up also has a wooden crossbeam in the way of the ring as well as another triangular shaped block. I have yet to do anything about this as well.
Finally, the 6511 driver hole on the left side of the left speaker and the 6511 driver hole on the right side of the right speaker also has a triangular shaped wooden block that you will have to try to pry up, move and re-glue or cut a portion away to get the ring in place.
There is a little extra work you will have to do to get your rings into your 3.1TL's but from what I have heard it will be worth it.
If anyone has some better ideas on how to do some of the things mentioned, please post them and add pictures if you thin it will help. I will take some picetures and add them because I think it will help. I will post them as soon as I am able.