Which one benefits more from a better power cord?

I would start with the DAC. But I agree with trying it both ways.

Not hard to do.

Well, the equipment are stacked in a vertical stand and handling and positioning Elrod cables are axtremely difficult, especially, the Statement which is humongous.

Of course, I'll try once to see if there is a difference but I just wanted to know if there is a certain preference.

I own 2 Elrod Statements which I use on my amps. I am not sure that the Elrod Statement is the best cord to put on either the transport or DAC as it is designed for amplifiers and power conditioners. The same is true for the Elrod Sig 3 cord. The Elrod Statement II and the Elrod Signature 2 are designed for the front end. When I tried a Signature 3 on my preamp - it sounded slow and heavy - that's when i emailed David Elrod to get a better understanding of the proper use of his cords. You can give it a try, but perhaps you might want to try some other cords for comparison purposes.

if no difference detected between two components mentioned you can take your desicion towards design point of view.

Since you own the statement already I would try a blind test experiment with a friend to see if the statement in various positions sounds better/worse/same to your own ears in a particular position. If you can hear a significant audible improvement and identify when/where the statement is in the signal path... then your tests would not only help you in your decision but would help others on this forum too (particularly those who might have difficulty justifying such an expense)...