Nice work on the mods. I have added a landing gear on the smallest build. Lego didn't include one, I saw one on a Dutch forum, but I thought I could improve on that. The skids don't sit completely flush like on the bigger models, but this is the best I could do. I had to alter the connection of the thruster as well as I used all the 1x4 technic bricks in the landing gear. I ordered extra parts to make the model a per instructions, but this works as well.
From here the Lego instructions can be followed again.