Chewy,
Just finished the zeera madras curry, with your base and Ray's spice mix.
I have made the Zeera madras several times since you posted it, with the Taz base and have had good results.
It really has superseded my expectations, the sieving and skimming really does make a huge difference to the consistency and texture also it really brings out the flavour of the spices in the final dish.
My conclusion is that the sieving and skimming takes away any bitterness from the base and puts the spices at the forefront and would recommend that this procedure would improve most base sauces.
I am going to speculate a little bit and say that the reason sugar is included in some recipes that really shouldn't require it, is to try and disguise the bitterness from the process, of not skimming and sieving in the base.
Top notch mate
Alan ;D
Most importantly Mrs moony is raving about the dish