Most coaches didn't believe Pendleton that she was a sprinter, obviously she proved them all wrong!
The power testing can only help, but coaches and power meters can be costly (even the use of a Watt bike or similar).
And, what works for guys on this forum may not work for you, many people spend many seasons sorting their training 'schedule' out. Everyone is different.
Lastly, as JMR said, if you're just not built for sprinting, training will only get you some of the way there - it can't change your genes.
Sorry if it didn't make sense, I re-wrote it a couple of times... And if you're set on sprinting are thinking about weights (as you mentioned in your post), everyone recommends the book 'Starting Strength'. I believe it was written by Mark Rippetoe? I haven't read/used it, but everyone else says it gives a good foundation to weight training.