The "fins" are the heatsink from an AMD Avalon processor package I picked up for $3. I cut it down w/ a hacksaw and drilled it out to screw-mount the side pieces and will use ceramic thermal adhesive to stick the top piece down. It will then be mounted to the project box/PS for the unit to go with my DMM.
This is more than enough heatsinking that I can measure up to 20W lasers...if I work out a better PS system for it...something wall-plugged.
Thanks, all. I am ultimately planning on using an 18VDC laptop PSU to power this setup. I just have to figure out the circuit. It will be complete with a high-current DPST switch and banana jacks to plug into a DMM and a USB connector for a future ARG board with data logging in it. In the meantime, I am going to enjoy this bulletproof DIY setup.
I still have another Ophir that I can build another heatsink for and package together for anyone who wants it!!