I've tried many, many speakers in my blackface DR's: original 50's and 60's Jensen P12Q, C12Q, C12NA...Electrovoice SRO and EVM...Weber P12Q, C12B, P12B, C12N...Celestion G12 alnico blue, G12M25 Greenback and Blackback, Modern Lead 70, Classic 80, G12H30 and Vintage 30.
The two "best" by far are what I've used in my two original blackface DR's now for several years: the Celestion G12H30 and the Vintage 30.
I slightly prefer the G12H30 for it's smoother highs, thicker and more textured mids and deeper and louder bass.
The V30 is brighter and has a little more of a hollow pluck to the tone and also a little less bass compared to the G12H30.
Lew