As is I would not go over 10mW for those types of modules, but the silver one is designed to be placed inside an industry standard 12mm ID heatsink, the black one is a standalone unit.
For laser rangefinder you're going to need higher output powers as the losses from atmospherics, real-world misalignments, and optics add up to be tremendous. Unless you use a VERY high Q optical filter on the receiver ($$$$) you need to use a very high signal to noise ratio to negate the influence of background light. I found this out when I build the laser communication system for amateur radio; anything further than 40meters needed more than 20mW to get a good S/N ratio, and I didn't even have to worry about a bounce mirror or retroreflector and its inherent losses!
Btw, why use a VCO when a simple crystal oscillator will have much more accuracy and less drift? You can even get temperature stabilized crystal oscillators relatively inexpensively on the surplus market. Working with super high frequencies has the added challenges of handling stray inductances and capacitances on the electrical side of things. You may find that the wire-to-wire capacitance of your driver or LD leads dramatically increases the rise time.
