The description says it has 6 3.5" and 3 5.25" bays. This seems standard? Is there something errant about the description?
The options I've listed will work with one or the other.
The 3.5" bays don't have slots for screws. The way they work is you put four special screws on the hard drive itself then slide hard drive into the bay. So the adapter needs to have screw holes on the side just like a 3.5" hard drive.
I have two Lian Li cases at home - one for me and one for my wife. Both cases have drive bays like yours. I have not experienced any problems using drive bay adapters. All you need to decide is whether you want to install the new ssd in a 5.25 inch drive bay or a 3.5 inch drive bay.
There is an International standard for drive bay dimensions and mounting schemes. That was developed to avoid installation problems. Mounting screws can vary by type of device but installation should not be a problem. Some cases also have drive bays that do not require any screws at all. For example the top two 5.25 inch drive bays in my Lian Li case don't use screws. I just slid an optical drive in and snapped a plastic retainer in place.
I ended up getting the cheap plastic one from Bytecc. It does the job, but the screws are difficult to attach and don't total secure the drive in place. Also, it's designed for just one SSD, though you could use it for two if you really want.