Candlepower is a tricky rating, my understanding is it's an estimate of the focus of light not overall output. The lumens rating gives you a truer estimate of total output which can be more helpful. You see, you can take conventional lights like a 3C or 4C Pelican and get 12,000 - 15,000 candlepower but the beam is so tight it has no business being used for tactical purposes. High intensity lights like the SureFire series, certain Streamlight models, Pelican M6 & others offer a broader beamshot that is better rated in lumens and more useful for tactical purposes.
I have a feeling you're pulling the 6,500 cp from the Streamlight Scorpion data?? If so, you'll find that the SF G2/6P type models that use the P60 lamp will matchup & slightly exceed the Scorpion's performance. The 65 lumens will certainly light things up far better than you expect; the beam will be much larger so you have better periphial vision of the area around your target.
The vertical grip and light positioning debate is another can of worms but it's a little late for that discussion tonight.