Yeah these off-branded ones aren't taking 3/4" (my understanding is that, if you're trying to fit 3/4" rope, you can't even use just 3/4" slot you need like 10% wider to account for flattening otherwise your rope's edges will be pressing-into the edges of the thing, hopefully they're smoothed/machined well!)
Thanks a ton for the recommendation am going to go check them out, am about to make a thread for help on choosing a heavy-duty rigging setup because I only have medium-duty now (so for my 1/2" lines these off-brand ones work great!)
Re the Harkens, that's good to know thanks! Re Ronstan, you mean oval-ID in a good way right? (can't tell which orientation you mean 'cross section' relative to in this context, still in coffee mode

)
Re the andonizing, I can't say I'm seeing much issue there in fact I'm uncertain there's much significance one way or the other insofar as how slick the rings themselves are (within a certain range of smoothness, obviously they could be too rough!), I mean the additional friction going from the slickest andonization to just rope-worn steel or aluminum, it can't be that big a % friction-gained and you could argue that additional friction is a good thing (to a point, but that point is well-below any friction from less-than-glossy rings!)
What do you use for your setup / what do you do with it, if you don't mind posting it? I'm unable to rig anything large so I can't even do a proper blocking-down of a tree right now because I'm trying to limit loading to around 1k lbs (1/2" line running through rings and either held or wrapped around the trunk at the bottom), gonna go make that thread to get an idea what I need for properly blocking-down a tree!