Actually I've tested that yesterday in TA ASAP.
I tested today, which is how I finally noticed what seemed like a dramatic change compared to my sketchy memory of when I 'learned the hard way' not to stack constructor modules in a design. The current TA UI is good--it doesn't let you make a useless design choice.
Re GmOOnii and speed 33 miners, are you doing that in a post-speed-'nerf' version of the game? Long ago, I built late-game combat ships with speeds in the 30s. But the devs came down on that pretty hard somewhere along the update/expansion path, so now anything with a speed over 10 seems amazing to me. Are you rush-building incredibly expensive hulls to get that speed in current TA or are you patient enough to let a starport work that long on one ship?