Usually extending holder are on a DR4B and tilters flip out, but it doesn’t have to be. The idea with passive extending holders is that they have multiple sections that can slide up to hold more cubes then the starting size limit. For slating most teams make a small four bar to mount the motor behind the tilter. Then you want a gear ratio for lots of torque.
Here are some good examples…
448X, 21S, 6671X, and 1437Z RI3D Reveal
1961Z Tower Takeover Teaser: Mk. III
Extending tilter: https://youtu.be/Wvz_8Ja-JQw
Check out this post…
https://www.vexforum.com/t/60449/421?u=codec
You probably heard the infinite part from…
DR4B Extending Reverse Stacker (V2)