scottdean...there is no single "correct" answer. There are multiple correct answers.
P and K are easy. As long as you only have one....they get 100% pt and start every game. If you have high POTENTIAL and a decent starting WE, those guys will grow nicely.
Other players are a bit tricky, but the concepts are the same. High potential with a decent starting WE...then the amount of PT and starts makes a huge difference when the players are young.
So, what is a "decent" starting WE? Well, you also have to decide what that is. I have a "minimum" WE that I look for in every player when recruiting. I will deviate from that if I find some guy who has really big core numbers and can start right away, but I usually keep that as a FIRM requirement.
It is also nice if you can keep a "minimum" for potential when recruiting. Try to NOT recruit guys who are L or VL. Again, I'll pick up those guys if they are already really good at their position and can play right away.
This is all a balance...it's hard to find a full class of recruits that: meet your position needs, have high WE, have high Potential, have good core attributes, and are actually available.
I suggest simply setting your minimum WE at something like 40....and let the rest of it fall where it falls....That alone will give you a bit of a boost...while you figure out the rest of the "magic combinations" that work for you.