Spartan-S63

That would be a horrendous waste of money. The program cost coupled with two launches would make it one of the most expensive (if not the most) programs in history. Might as well pack up NASA and never revisit publicly funded manned spaceflight again.

Good news is that after 1.2 hits, the fuel flow settings might allow you to ditch all the fuel ducts around the tank. We'll see if it works though.

One of the things to try to replicate the roll program is to make sure you're using SRBs with gimbals and only use the SRB gimbals to execute the roll. Using any of the SSMEs modifies the torque on the vehicle and causes you to deviate from other axes. This also requires that your SRBs produce much more thrust their your SSMEs.

Any chance this is being added (or has already been added) to CKAN?

Yes, it is. I don't think it really matters though because the rotation tools can flip it around in the VAB/SPH.

Just flip it around so the attachment node is faced towards the Mk3 cockpit.

It's going to be this one: I use it too and it's a pretty great IVA overhaul for the Mk3 cockpit.

By chance, do you use the SSMEs for the roll program or do you do it some other way? I remember hearing on someone's stream that the SRB gimbals execute the roll program on the actual shuttle and that's why it didn't deviate too far from its velocity vector when rolling. On lift off, the SRBs generated the most thrust. The SSMEs existed on liftoff to make sure the torque on the vehicle due to the offset CoM was essentially zero.

That's the best you're going to get it. It's fine so long as you're flying straight and level. As soon as you start rolling to turn, you start inducing a side slip. If you rotate the vehicle in the SPH and look at the CoM and CoL placement, you'll see that the center of lift acts differently when the vehicle is no longer belly-down. There's really no good solution to the issue. It's mostly just being gentle with the controls and understanding what your flight characteristics are.

It's not an issue of my nose wheel, it's actually when my main gear touchdown, the spring compression ends up bouncing me back into the air a good 50 meters or so. Maybe I'm not slowing myself enough for touchdown that it bounces me back into the air and I continue gliding. Again, I'm touching down around ~100 m/s. I typically try to stay above that because any air speed below and I have a hard time raising my nose again. Then again, I'm typically pitching at greater than 10 degrees on touchdown which is pretty steep for main gear touchdown.

I'm really excited to see the possibility of a split-rudder being included in this mod pack. In the past, when I've tried to do this through mirroring the tail, I've ended up weird situations where control surface reversal would end up deploying the rudder in the same direction, inducing a massive yaw, and resulting in a flat spin. It's really frustrating and I'm sure it's a mod conflict. To see a part that supports it out of the box should fix the issue and seeing it deployed via action group is awesome too. I love this mod, thanks for all your hard work! Also, does anyone have any advice on how to solve the issue where the landing gear are extremely bouncy? I keep having the issue of touching down and then bouncing back up into the air pretty high. I've tried adjusting the spring and damper but I don't really understand how they work well enough to fix the issue. I'm also touching down around ~100 m/s which is pretty fast to be going. Any less and I have a hard time pulling my nose up. I'm using FAR, by the way.

Excellent, I'm definitely checking this out! Edit: Checked it out. Wow, your TWR on the shuttle is ridiculously high. There's no issue with that, but I totally underestimated how aggressive my gravity turn should be. That thing flies like a bat out of hell, wow! Perchance, did you do "drop tests" with your shuttle orbiter to test the glide characteristics? If so, did you build a shuttle carrier? And if you did that, how'd you build it? I'm still having trouble making my shuttle a sub-assembly that I can attach to a larger jet-propelled aircraft or whatnot. Any advice would be awesome!

Yeah, you should definitely roll and pitch up once your above most of the atmosphere. The torque pushing your nose up is favorable versus the alternative of pushing your nose down. That said, I'm still working on mastering the roll maneuver without introducing yaw or pitch.

For balancing the main engines, I use Kerbal Engineer and continue rotating them until I get as close to zero torque as possible. The mod shows you how much torque is created by the offset thrust. Also, draining fuel from the bottom first and then the top (which I haven't quite figured out yet) will help you when it comes to keeping the stack balanced as you drain fuel. You want to keep your CoM as high as possible for as long as possible so the thrust vector doesn't have to be too terribly far off center. It also helps to drain the bottom fuel tanks if you don't need them for deltaV.

I haven't fixed this problem yet, but I would imagine using something like RCS Build Aid, you could balance the RCS by adding a few more thrusters around the body of the craft to make sure that no weird torque (I think?) is being applied while using the built-in RCS thrusters.