Your assesment of the salary of a typical d3 center is on target.
I'm in a leauge where the center is making upwards of 90k on a few teams......mine is almost 70k,worth every penny.
You can win with a 25-35k center there, and can actually compete there too, he just won't dominate mearly hold his ground.
But that salary may not be a viable option in d4. Upgrade on the fly once you promote, and hopefully you arena is big enough to get that type of player mentioned.