you can get One Set of double super clamp like this, don't need to buy two super clamps plus dual sided 1/4 inch bolt to attach two super clamps together.
and you can use an Alan key to remove two bolts (same size as the Acra Swiss camera Plate bolt) for separating the double super clamp into two individuals super clamps if you need to use them individually.
Thank you @catchlights for the info! Very helpful, indeed!
Wondering where I can get "Manfrotto 208 3/8-Inch Mounting Plate" (preferably 208HEX, a newer version) in SG. I know Cathay is a local distributor for Manfrotto, but they don't have this accessory (just checked). Is there anywhere else I could try? Thanks in advance!