You are calling this a "short" but we need a little more info.  Does this condition cause the battery to run down in a short period?  When this occurs does it cause any fuses to blow or smoke to be released from the wiring?  Does it just cause something...headlight, etc, to not function. 
Battery running down is a drain and can be caused by something as simple as a sticking closed hydraulic brake light switch....just ask MS.  Blown fuses are an indication of a real 12V short to ground.  Hot wiring, smoke, melting insulation are indications of a serious short to ground through a circuit that is not fuse protected. 
So.  We have all been down this road one way or another and will help all we can.  But please provide a few more details.

OH, and welcome to the best place on the web. 
 

Along with the brake light switch (this issue is more prevalent on the ‘pressure’ type brake switch mounted on the master cylinder), check to see if the glovebox light is off with the door closed, if you have a new radio with ‘pre-set’ stations and/or clock, power is always ‘on’ and will always draw some power.
 
If you’ve left the car for two months and don’t have issues starting, why do you think you have a problem?
How old is the battery?  And, what is the battery voltage when you leave setting for a few days?
 
Is an alternator and generator installed?  Either way there could be something with the voltage regulator.

Just a note; there are voltmeters that fit into the cigarette lighter that can be purchased for under $15 from Amazon.  I checked the one I purchased against my Fluke meter and it was within a tenth of a volt.  It’s a easy way to check things out.

Thank you all! The answer I was looking for is that this test is to find a battery drain and that the 0.07 volt draw is nothing to worry about. I should have said I have two and probably more electrical problems. I wanted to find out if the 0.07 was enough to be a problem. Got that answer. I also have a short that only happens when I remove or replace my instrument panel and that does blow the fuse and melts the headlight switch. I have replaced it 3 time already. Not cheap at $20 a pop. MS has wisely said quit fooling with it and leave it alone. I get around that problem by removing or replacing the instrument panel only with the battery disconnected. Again, thank you all for providing the answer. Too small to worry about and what that test if for. 

I learned many years ago that a gold wedding ring makes an excellent electrical conductor, always removed the battery ground after that when working around electrics.

Bullet Bob wrote:

As for the .7 volt you read.  I agree totally with Walt...it's nothing.  I've seen way more than that with both cables removed.....very dirty battery leaking voltage across the top, post to post.

It was only 0.07 volts, not 0.7 volts.

On the short it sounds to me like there is a constant power wire (yellow most likely) that is making contact with a ground as you install the instrument panel.  There must be a spot in the insulation that is cracked or missing.  I'd think by now you'd be able to see evidence of it arcing. 

These guys are spot on, anytime you mess with anything electrical first order is to remove the ground cable from the battery. 

BB, my grandfather used to call a wrench a Bahamian battery tester.  You see some stuff after spending a lot of time on a tiny island...
 

Jose – I’m curious, which fuse are you blowing?  The headlight switch is not fuse protected; it is directly wired to the battery via the Black/Orange (#25) wire that is spliced to the Black/Yellow wire (#37), that goes to the fuse panel, and gets 12v power from the starter solenoid.