I have Kadet Senior with balsa pushrods as the kit describes. Everything works just fine.

It works because mine flies really slow. Slow speed means much less pressure on the control surfaces. The same setup might be a bad idea on a faster plane?

Unless you're flattening out the wings, adding weight, clipping the wing a few bays and/or putting twice the engine in it, it will continue to fly as slow as it was designed.

The pushrod tubes are often easier to install, but the Kadet doesn't have any bulkheads in the tail to mount them through.

If you're worried, the dowels sound like a good idea, but if it makes the model tail heavy, you may be adding a lot more weight than you realize.