Never read that to be honest, but I dont believe you even need claims, it can be done faster (albeit with a little higher cost) if you go for religious supremacy. Especially now that they removed a whole chunk of territories from the middle east.
I don't understand what you're saying here in terms of "religious supremacy" - or do you mean divine supremacy? Or are you thinking of deus vult?
The reason to have CBs from Cyprus is that as an eastern tech (anyone really), the lower coring cost from having a claim pays off. So if you look at the number of provinces that Cyprus "borders," albeit from the sea, and compare that with the typical number of bordering provinces wherein one can forge claims and then calculate the cost savings of the reduction in coring costs, Cyprus is a hugely efficient place to take in order to proceed to wage war.
In any event, you need a source of CB. Deus Vult will give you that as well as saving diplo MPs but best is to have a claim even if you have religious ideas so as to conserve admin MPs. Even better is to consider skipping religious ideas, which really aren't necessary given the missionary buff Byantium gets from its NIs and go for admin ideas to straight up reduce the coring costs further. Even then, forge claims because the reductions to coring costs combine.
You should always be forging claims to reduce coring costs, unless, of course, you find a glitch like DDRJake did wherein you core for 0
Short of that, remember the *math* involved in making decisions. Claims == lower coring costs == more Admin MPs available for more provinces to be cored, or more ideas or levels or whatever.
And, as usual on these topics, the *math* is what matters most.
So, forge claims, always, unless it's a reconquest on one of your cores. The math says to do so.