I apologize for the book:
Everyone is correct to a degree. For the most part there has not been a bar available with an adjustable "leverage" point. Eg: A longer mounting point with multiple holes. Adjustable end links would be the most effective way to finesse the rate of the sway bar over changing the mounting point. Unless you are trying to go beyond the 24mm Progress bar and achieve a ton of oversteer. At that point you would be a track master and not be reading this forum for tips on improving the handling of your Civic.
Both leverage and thickness play a role in the effect a sway bar has on the suspension. The thickness is multiplied by the sum of squares. Upgrading to a larger rear sway bar has been a quick and effective means of creating more oversteer on a car that generally has a ton of understeer. For a cheap amount of money you can effectively improve the handling characteristics of the Civic by using a larger rear sway bar. The small upgrade from 19mm to 22mm results in a 34% increase in rear stiffness. Bam, instant available performance you can feel right away. Its proven, effective, and cheap. It has nothing to do with geometry or lever arms but with simple uprating in the sway bar itself through an increase in size. Keeping the same size bar but changing the geometry of the lever arm will provide the same changes but perhaps not at the same rate. Also, not being able to keep the lever arm perpendicular will not be an improvement in handling which is where adjustable end links once again become an important part of the setup. For most end users, adjustable end links are a constant PITA with noise and the need for a proper corner balance alignment.
Just buying the 22 or 24mm progress rear sway bars and utilizing the stock end links or the solid Moog end links have proven to be a hassle free, cheap, and effective upgrade. Not knocking the CT setup but hey, if it ain't broke, don't try and improve it unless you're an engineer. Also changing to aftermarket suspension setups with different spring rates than stock will have a huge impact on handling and the setup of the sway bars if you are going to start playing with lever arm distances and endlnk lengths. Keeping everything static to a point will help a ton in deterring what changes need to be made to get the car to a balanced handling point.
If you just bang every super stiff part there is out there onto your car is may feel like it handles on rails but isn't actually cornering better than your grannies civic. The suspension is a game of balance. Spring rates, sway bar rates, and tires are a system. So far no one has had any bad effects from a larger rear sway. I doubt using one with a longer lever arm will change much.
Bars with multiple holes are changing the lever arm:
Using a longer lever arm adds preload. Bars with more than one mounting hole add more preload. Adding preload to a sway bar effectively increases its rate or makes it feel larger than it is. It is not as effective as fully upgrading to a larger sway bar. We are talking about changing the rate of the sway bar in orders of magnitude. You could easily achieve the same difference by utilizing adjustable end links instead or a bar with multiple mounting holes to change the rate of the bar. Overall an increase in the thickness of the bar is going to create the kind of change you can feel and use. Adjustable end links and multiple mounting holes are for when you are trying to achieve a certain balance in the car. The setup from the factory favors understeer so badly on the Civics you will not need to lessen the effect of a larger rear bar with a lesser lever arm on the sway bar unless you are a track master. At that point the simplicity of the larger rear sway would be best served by using an adjustable end link and fine tuning from there.
Same effect, different way of going about it. For example you could get grip from wider tires or from a stickier tire compound. Same result, different way of going about it. Hopefully that makes sense.
This is a long answer depending on how much you want to get into the physics of race car handing. I could write you a book on what I've learned but here is a great resource. If you don't understand it you need to keep reading.
http://www.vikingspeedshop.com/the-truth-about-sway-bars/
TL : DR
The larger the change in diameter of the bar the more noticeable the effect vs a longer lever arm "blade" mounting point. Changing the mounting hole effectively changes the rate of the bar. So do adjustable end links. The hole/endlink solution lets you feel like you have a 21.5, or 21.7mm bar instead of a solid 22mm bar. We are talking negligible differences usually. Its big changes vs small changes. Just get a larger rear bar unless you are running race level suspension.
Super TL : DR - Buy the big bar. Don't waste your time on adjustable end links and longer "mounting holes" unless you seriously understand what you are doing. The incremental changes on a street car aren't worth the hassle/worry.
