Well, I can share you grieve.... I had some really interesting embark sides for .14/.16 (sed.flux + met.flux, sand, lotsa metals, volcano, etc.) where I could change neutral + good or evil biomes via a change in numbers of natural caves during creation, somewhere down the line I even had a neutral+evil+good biome side with all I want in it).... for .18 it was a PITA to find something suitable and now for .19 I stick with the one I posted in the
worldgen cookbook thread. Once Today is down to a version where worldgen wouldn't change that much I may be again venturing for an ideal embark, but so far I settle with less than optimal)... trying the new features out is time consumptioning enough IMHO, and having an perfect embark side isn't worth anything (IMHO again) unless the world parms would regenerate that side with the next version also%> :insane:
One of the best tips I had found in this forum to get a good embark side is to set lowest and max vulcanism to 2500 (wich often brought me sedimentary flux and metamorphic flux + sand).
I am also adding a min. rainfall of 5 and some altering to the temperature settings (+some endless changes I kept with experimenting since .40*.... once you have found a good embark, save that world seeds and try to experiment with number of civs or number of natural caves, etc. and if you then get a really cool side you may experiment with sticking to that parameters and world seed and only randomizing history and creature seed (name seed is well, optional).... and once that got you your dream side you may again finetune ("crossmerging") with things like number of caves, number of civs, erosion cycle, etc.
In short: find a good basic worldgen recipe that provides you with the worlds you want and then find one seed where you start to experiment with the details...
But I must confess, for .19 I so far was unable to get any playable civ. that starts with bit.coal, lignite was all I got so far - and no civ. I had experienced in this version ever had bauxite for trade.
But at least with my current world I have no problem with flux and metal, either I have it on side and/or my parent civ. is able to sell it to me.
Ok, long post - only real 2cent of mine: stay with the first suboptimal best world/side you get for now - this DF2010 branch is far to new and ever changing to waste time on finding an ideal embark [edit: meant "perfect embark", as I know no one of us would settle for less then ideal]...