Reader Goody (love that name!) says she can never get choux to rise well. The puffs brown but are moist on the inside and seldom have the very large spaces she wants. Goody, I can think of a couple of things you might try. First, when you’re making your choux, be sure to cook the batter long enough before you add the eggs. It could be that you’re not getting the starch breakdown you need to form a nice, elastic batter.
Another possibility is that the batter is too wet. If you’re using extra-large eggs the batter can become so slack that it puddles on the sheet and has a hard time lifting off. So make sure, in the mixing step, that your batter is always firm enough to stand up on its own. Stop and check after the third egg is completely incorporated. Stand a blob of batter on your finger. It should have no trouble holding its shape. If you’re in doubt that the batter can incorporate another whole egg without getting too soft, add just the white and stir it in fully.
Next, check to make sure your oven isn’t running cold. Choux relies on a big blast of heat right at the outset of the bake. It’s the big heat that creates the burst of steam that inflates the puff. If your oven is running cold you won’t get the expansion you need before a crust forms on the outside and restricts the remaining rise.
If you try all that and still can’t get a decent rise, try switching to a higher gluten flour. Bread flour will give you more gluten, a stretchier consistency and a higher rise. Be aware that a sky-high rise isn’t necessarily a good thing either, since it can create thin walls and deflation, but it might be worth an attempt. Along the same lines you can also try cutting back the butter by about 25% to see if a lightened fat load helps (it often does). And that’s about all I can think of, Goody! Best of luck with the puffs!