Tonearm cabling for Graham Phantom

Right angle or nor depends on the Space you have below the Armboard. With the Raven Armboard you can use both. I use a right angle one for example.
There are lots of choices out there. Depends on the Design (shielded, real Phono Cable or rebranded RCA), the interaction with the rest of your chain, copper...silver....
I made last year a comparison with
PAD Venustas
XLO Signature Phono
Siltech Phono
Graham IC-70
Kondo KSL-VZ
Cardas (their latest at that time)
and a few others I forgot.
The PAD can create a huge soundstage, but I did prefer the airy Speed from the XLO, the Graham IC-70 was another cable which showed a very good balance in all frequencies from top to bottom.
The other ones were much more expensive but didn't show that kind of balance, most were dominant in one or the other area.
When you use the Search here you will find lots of posts about Phono cables.

OFC copper has a Conductivity of 100 (from AES=Audio Engineering Society) and is the Standard in Audio.
Technical silver has conductivity 106 (Gold btw. 90)
That means, Silver can carry 6% more information than anything else. This is fact.
But, it can be decreased by the kind of solder, the kind of plugs which are used (cable or Phono input), from the Phono input to the cable ...
Bob Graham did his homework and delivers his Arm with Silver cable inside, his own IC-70 is silver cable...
You can ask 50 audiophiles and you will get 50 recommendations, that is fine, but what you do when from these 50 only 5 made the right decision?
It is better to trust Physics, it can help sometimes :-)