Doubling the voltage will halve the current.
Regardless, keep an eye out to be sure that you are not overloading your circuits and use 12 AWG (3.3mm^2) wire or larger.
You can get correction filters for tungsten to daylight conversion. Rosco Cinelux gels will do the job. Find them at the link I gave above.
You can also buy "frost" gels to go in front of the lamp to soften the beam. Many makes of lights have adjustable "beam spread" and "focus" controls to alter the width of the beam and the softness/hardness of the light.
As Mike says, try to get fresnel lights or "scoop" lights instead of spots or "Lekos." They'll be more like the kind of lights you are used to using in the studio. There's nothing wrong with having Lekos/spots if you can get them. You'll just have to move them farther away from the subject if you want even light.
Lekos will, however, provide some really dramatic lighting effects if you are willing to experiment!