Hi ttan98
I have not played with the delta lites yet. Hear they are good though.
Could be way off base from what you are conceiving but;
Have you considered the Alpha 8a? (Haven't played with it yet but other have had good results)
Disadvantage:
Higher Fs so distortion might rise faster below that.
Less power handling.Advantage:
Flater responce.
higher cross over possible.
Better midrange dispersion.
Should go just as low as the 2510 but at lower volumes.
If it fits your design parameters you might use more drivers. Like 4 instead of 2.
Just a thought mind you.