Keep in mind that prestretching does help reduce tension loss but you lose some the comfort that comes with a multifilament string. The result is you reduce tension loss but the stringbed may not feel as soft as you would expect.
I can vouch for cruzers indication of the Prince Premier being stiffer when pre-streched. I currently have one of my racquets with a prestretched premier 17 g and I did notice it being a little stiffer than when I had previously strung the same string at the same tension, but without prestretching it. I think the key is to not over prestretch. Pre-stretch, enough to get the coil memory out of it, but don't prestretch it as much as you would do natural gut.
The best way to prestretch is to do it with one continuos pull. Find a padded door nob that you can loop the sting around. I use a floating clamp to hold the loop in place on one end. For the other end I wrap the string around a soft rubber screw driver handle and just lean back a little.