One can obtain the "drop position" without holding the bars on the drops. Hold the tops with hands close to stem, forearms parallel to the ground and chin to the stem.......variation of being in the "drop position" with different muscle use. Forearms on tops with hands forward of bars clasped or not, BUT this requires more skill.

Drop riding was once very comfortable for myself but now I use aero bars. They provide more comfort and thus better expenditure of energy for forward movement. In 3 weeks after a shoulder joint replacement, I am hoping for less pain and a return to more drop riding; HOWEVER, aero bars will still be my number one choice for an aero position.

Do all the core work and stretching you want, I never did, but actual drop riding is still the best way to get comfortable and efficient.