q1] this of course depends on your entire doubling call structure. I would use it as having an ordered series of possible meanings. Initially it means "I can play either major, I need your preference." q2] a 1 round force q3] a minimum TOX with no major preference. q4] xtras with a max of 3 cards in either major q5] minimum TOX with ♥ preference q6] minimum TOX with ♠ preference q7] balanced 18-19 with ♦ stopper(s) q8] minimum TOX with 33 majors q9] xtras with no great preference between the majors. q10] xtras if a major preference or a really good ♣ suit q11] I think previous answers should make this clear q12] no q13] 4 card constructive raise of ♥ and ♠ q14] this is where other possible means for 2♦ kick in; really telling partner we are in a GF q15] GF with 5+ ♠ q16] that you need to review your doubling structure from time to time :)