I used to use a pinpoint as well. Helped with power and serve and volleying.
It forced me to really get my weight up and into the court.
After taking a long break from tennis, when I started again,
I initially started with a platform stance b/c my toss wasn't that
accurate. Kind of just stuck with platform and that's what I use now.
FWIW, my serve is not as big as it used to be. Maybe 10-15 % worse, but
that may have more to do with me serving /playing less regularly than
http://goo.gl/NPBIWt (How to serve like Sampras)
http://goo.gl/KZfDaJ (Star Wars superfan battle)