If you do, be bloody sure you embark in the correct section of the map! I take no responsibility for making contact with the wrong goblin civ, thus locking your fort out of meeting with Gedor forever and ever.
Here's a region that should work, as it is really close to the fortress Gedor's been defending for the past century and a half:
The selected region has hematite (11970 units) over all but the bottom right quarter of the map. In that bottom right quarter, it instead has 1122 units of native aluminum. There are also 260131 units of native gold on the map. There is an aquifer over most of the map, but not all of it - you can find stone on level 124 which will allow you to bypass the aquifer entirely. When I test-embarked with reveal, there were also two serpent man civs underground - one with cave spider venom on their darts, the other with GCS venom..... Both are in the first cavern layer, which goes up to level 97 and down to level 93; it has a stairway connecting it to the second caver layer (bypassing the marble, which is on levels 76-68). The second cavern layer goes from 10 to -5 and has a huge lake at the bottom, as well as a deep pit connecting it to layer 3. Layer 3 goes from -14 to -18 and has two exposed magma pools right into the magma sea. Also, if you use reveal to be absolutely sure you don't breach magma or the circus, you can safely get exactly 333 units of cotton candy.
Should be fun. I'd consider joining in the succession game, but I really want to try an evil embark right now. ^____^