Where would you put better power cable?

Currently I have my pricier cable on my dac being a thicker gauge with better connectors.

I doubt that gauge and connector quality would be responsible for any differences that may be perceived between power cords used with a transport and a DAC, assuming (as appears to be the case here) that both cords are of reasonable quality in those respects.

Shielding and noise rejection figure to be the characteristics most likely to make a difference in this kind of application. However, which of the two components would be more critical in those respects is dependent on the specific characteristics of the noise on the incoming AC, on the sensitivity of each of the two components to that noise, on the characteristics of the noise each of the components may feed back into its power cord, on the sensitivity of the other components in the system to that noise, on the susceptibility of the two components to ground loop issues, on the proximity of each power cord to other cables and power cords, etc. In other words it's all essentially unpredictable, IMO, as several of the others have indicated.

Also, I would by no means make a general assumption that higher price correlates with better shielding and better noise rejection, or with any other characteristic that may make a difference. Although based on their descriptions it appears to me that the higher priced of your two particular cords probably does happen to provide superior shielding and noise rejection.

Regards,
-- Al

Al, Your second paragraph is particularly and succinctly well put into a liking as audio poetry and fully spelled out.
The only downside is that it ended the need for any further cable matching questions on this site. Thank God:)

Thanks, Iso. Poetry, and related to that alliteration, have never particularly been my bag. I do, however, generally try to avoid being a nihilistic nabob of negativity. :-)

Best regards,
-- Al

Al, Your natural nature negates negativity:)

Upgrade every cable ASAP!!