Do you know the notes in all of your diminished chords? If not – here is a shortcut method that works provided that you know all chord tones in your dominant 7th chords.
Here is an example:
What are the chord tones in an F# diminished 7th? The shortcut is to use the root of the diminished chord with the 3,5 and b7 from the dominant 7th chord a half step below. So we would combine the A,C and Eb from the F7 with the root of the diminished chord.
The notes in the F# diminished 7th chord are F#,A,C,Eb.
Hope this helps!