Dont worry about copying. I would have done the same but my I was one of the first 05 X owners so I had no body to copy. I just dived in and did it.
1. Do you know how many cubic feet the enclosure you made provides? Looks like the 10" type R I bought requires about .6 -- I was thinking I might need to drop down to an 8" but thought I'd check in with you first.
It provides about .6 +/- 10% which is within alpines range on the specs for a 10". I actually filled it with mulch to get a fairly accurate volume measurement. I use mulch cause that was all I had access to that was easy to work with. I suggest sand if to get an exact measurement. Make the box to an approximate measurement. If to big add a 2x4 chunk. If to small cut off on of the ends and re-do it. My advice is to keep the 10" as you have plenty of room. It will hit deeper and move more air. Combine it with a 600 watt alpine amp and it will shake the X. But if you truely want bass and love rap music you need two 10"s and 2 600 watt amps. I am very happy with my setup as I am not a huge rap fan. Its very loud and more importantly crystal clear. I literally hear stuff in music I never head before.
2. Any tips on brand of fiberglass - is there a kit that you recommend? Any other tips on working with fiberglass - I have never used it.
Walmart baby!!! Got all my stuff from there. If you can find a marine place where you can buy a gallon of resin I would suggest that. You may get a better price on a larger quantity. Just do a price comparison.
There used to be a few very good web sites that showed "how to" but I just checked them and they are not online anymore which stinks because they helped me a bunch.
Do you need a quick how to? If so I will post a seperate "how to" in this section since the online resources I used (which rocked) on the web do not seem to exist anymore (sucks).