Question about mounting UcD amp modules

I bought some remarkably inexpensive amp modules from China on ebay.
They are UcD based and compatible with the Hypex 400A400 power supplies I have.
Unlike the OEM modules they come on robust metal plates, much like the real Hypex modules. They aren't direct clones though - they have single ended inputs which is handy for the rip and replace I'm looking at. As well as being cheap.

What's the preferred way to mount things like this? There are a couple of holes in the bottoms of the plates that I could perhaps use by drilling the bottom of the amp case I'm reusing, but I'm wondering whether double-sided thermal transfer tape would work OK, and/or heatsink glue - and just glue them to the base of the amplifier.

There's no instructions, but the pins on the modules are labelled. If they don't work out, I'll get some real Hypex modules but I don't think I can get 6 channels in the case I have, which is what I'd like to do. The modules I bought are a mix of 1-channel and 2-channel, and while the case had 8 off UcD250OEMs, I can fit 6 channels in like this..