Hi wilkes,
1. Headlight and light implies low swingweight. Here are the specs for that Fischer Vacuum Pro 98 that recently sold on flea bay. I think you've focused on the racquet being 16 points head light, and are making that a proxy for something that is easy to swing. At 12.3 Oz, I think a more appropriate perspective would be to call it tail heavy. Just eyeballing those specs, I'd guesstimate the swingweight is somewhere in the 310-330 range.
Head Size: 98 sq. in.
Grip: 4-3/8 in.
Length: 27 in.
Weight: 12.3 oz. strung
Balance: 16 pts. head light
String Pattern: 16 x 20
2. If low SW is truly what you are after, then you dont want to modify the pallet of a shorter junior racquet, you'd do better to approach it the other way around. A better start would be to chop down an extended length frame. Racquet companies understand that adding length creates maneuverability issues, so extended length frames are built with that in mind. That's why you will often see them at low SW and 12 or more points HL. Chopping down the extra length would drastically cut the swingweight from there. Corners has a thread going that discussess the search for the lowest sw frames avail. Might check that out.
http://tt.tennis-warehouse.com/showthread.php?t=451549
the lightest most head light racquet made guess and string for power? yes, the suggestion for Head racquets has been made (remember you can still older ones made in Austria/Cezch)++.
3. I've been trying to figure out where you are coming from, and I think I can intuit/guess what you are trying to achieve here with the statement above. Perhaps you have in mind to have a racquet that is very easy to swing, a racquet that is super maneuverable, but then you'd make up for the lack of mass in the business end of the stick, by stringing for power? I think you might be severely overestimating the effect of string tension to racquet power, and underestimating the effects of swingweight. If you drop tension from 60 lbs to 50 lbs, you are likely to gain whopping 0.4 MPH on a 100 MPH serve. Strings and tension will make a little difference, but mostly, ball speed is a matter of racquet head speed and swingweight. (mass times acceleration) If you'd like to swing really fast, and get your juice that way, then a light racquet will help you do this. As an added bennie, you will create some additional spin out of the deal. But string tension/type of string, are going to only help out with the reduced inherent rebound power of a low sw frame by a fractional amount.
-Jack
