TDA7293 supply voltage bypass caps

I have a guitar amp that I am fixing for myself from a manufacturer that does not make repair info public...no schematics, no parts. So i reverse engineered the power amp stage but am reluctant to post it in case i break the rules of the forum. So instead i will describe a circuit in the stage and ask for some advice on it.

The stage is based on a single TDA7293. The amp is rated 75 watts thru a single 12", 8 Ohm speaker.
It uses +48V for +Vs at pins 7 & 13
It uses -48V for -Vs at pins 8 & 15
Following Fig. 1 'Typical Application and Test Circuit' in the datasheet, the values for the supply voltage bypass caps are as follows:
C6, C8 - supply voltage bypass for both +Vs and -Vs = 47 uF
C7, C9 - supply voltage bypass for both +Vs and -Vs = ?? uF

C7, C9 are surface mount and appear to be beyond the range of my multimeter, which goes to 20uF AND i am not sure if i can get an accurate reading of the caps IN CIRCUIT (same as datasheet).

My question is, is it possible to guess at the appropriate value of C7, C9 based only on the values of +Vs,-Vs,C6,C8 and the values shown in the datasheet?
If so, how would i determine these values? Can anyone tell me what they should be and why?

Thanks,
JBro