Campagnolo Centaur BB fitting woes....

Just bought a 111mm campag centaur BB to go with some DA7600 cranks.
The BB is slightly different than many cartridge units in as much that the spindle/bearing assembly isn't attached to the right side cup.
Instructions say install DS cup and tighten to 70nm.
Shove cartridge in NDS until bearings locate in DS cup.
Install NDS cup and tighten to 70nm.
There's a caveat that says if tightening to 70nm increses friction too much, to back out the NDS cup, apply threadlock and re-tighten to 30nm.
Now, even at 50nm the cup is obviously applying way too much pressure to the bearings and the spindle is notchy as hell to rotate. Even at 30nm it's notchy.
Basically anything over hand tight applies too much pressure. I would not be at all happy riding this with the NDS cup finger tight with threadlock.
Has anyone any suggestions?
I've read of this exact same problem happening to others but no solutions. I'm guessing I'll just return the whole BB as faulty and use a cheaper one for now. Either that or just bite the bullet and use a JIS and hope for the best....

Perhaps you could use a spacer ring behind the Drive Side cup? I've done this successfully in the past when I've encountered a similar problem. I got mine from a shop that deals mainly with Single Speed bikes and conversions and they were available in various sizes.

This, quite often the crank/BB/frame interface isn't that accurate. Like when people are eating through SRAM GXP BBs because they're 1mm out. Think Velosolo do a little spacer pack for free hubs that I used on my BSA GXP.

Yes, that's the supplier I was alluding to in my post. Wasn't sure on the posting rules in naming places, hence the not so cryptic description. I've found numerous other uses for those spacers - find them very useful.

posting rules in naming places

If it’s an advert, please don’t. If it’s a voluntary, useful recommendation, please do.

Hey thanks. I did actually try that but all it does is pull the whole assembly to the drive side and the problem remains. The thing is, like a lot of these assemblies the NDS cup doesn't have a shoulder on it so it tightens agains the NDS bearing.
I'm not certain it's even supposed to be pre-loading the bearing in the way that it does. There's a central sleeve that looks like a dust cover which I 'think' is what the NDS cup is supposed to tighten against. But it doesn't, it tightens against the bearing. Hence even 30NM is enough to bind it.
I've tried multiple BB's in this frame and they all sit perfectly so I'm certain the Campag BB is junk. Given up on it now so am going to send it back to the supplier and buy the Sugino.
Out of interest, I did actually buy a Tifosi just to try but as a few reviewers had suggested, it's ever so slightly smaller than JIS but nowhere near ISO! (despite being advertised as Campag fit)

Just a quick update.
Bought the Sugino 75 cartridge BB. After removing the Campag and cleaning everything up, got some copper slip on the threads and the Sugino was in, torqued to spec. and up and running in all of about 5 minutes. No grief, no binding etc. piece of cake!