Thinking about getting a CSI pad. I have heard that some of the complaints are of it being too bulky. Would getting a 1/2" liner make it a little bit more manageable?

I have one with a 1/2”.

I don’t love it because if it’s thickness.  But we keep it around because it is occasionally the best fit for a particular horse/saddle combination at a given time.

I agree!  I sold mine because I hated the bulkiness of it.  I had a 1/2, and it was still too much for my taste.  But, that's personal preference.  I hate the perched way on top of a horse feeling that you get with some saddle and or pad combinations.

If I'm struggling with fit, my go to is a saddleright with some homemade shims as needed until I can find a different saddle. 

I don't really like the thickness on the CSI's. But I do have the 1/2" one that I use on my 4yo. Just because he has some more growing/ bulking up to do. That is the only reason I keep it around. 

The CSI pads are a cool pad, but not for me I tryed one befor I was going to order one, but since my saddles are a pretty good fit on my horses the CSI was just to much..  Oh I agree with the perched feel, that I did not like at all.

I ride my CSI  pad with a Jeff smith xtreme Barrel saddle  and also a Csi with my roping saddle and no complaints at all. I love mine. My barrel saddle pad is the “standard” size/shape flex plate with 3/4 insert with the shorter length of 30” - it took two or three rides to break it in but it fit from the get go and I feel like it definitely keeps a treed saddle from rubbing or putting pressure points on a horses back or shoulder.  Haven’t needed to chiro my horses since I went to CSI pads. if you get one pay attention to how to position the pad under your saddle - basically want to slide your saddle to the rear of the pad with more pad in front of your saddle than behind it- there’s pics on the directions they send with it. I prefer the 3/4 thickness insert even for my barrel saddle but can see how a 1/2 would be enough in most cases too - the website says to use a 1/2 inch for more round backed mutton withered types.