Vox's Solution

K Kermit Savage heard ok 60
A A toke marked his grave 53
D Dame Kirk hoes vat gear 46
A Armada verge the kiosk 57
V Vigor me sake hard Kate 48
E Eke as dogma thrive ark 51
R Regret ham dive ask oak 49
G Gave hoer dark mistake 58
E Evade grate mako shirk 55
H Have kismet goad raker 56
O Okra give skeet dharma 56
R Ravage mad kosher tike 58
S Savaged hero maker kit 59
A Avid geek markets hoar 58
M Meek avoid great shark 55
K Karma god save her kite 47
E Ever make ska ado right 47
I Item rave hark dog sake 46
T Take ma shake over grid 48

Total 1007

Just a few comments on the puzzle for you. As we have played it on scraps of paper, i believe that has contributed to its difficulty. Were it presented as a game that you could play on your computer or-what-have-you, the game could keep track not only of your score, but more importantly, what letters you still have left to work with. My sense is that if this is to continue being something done on paper, the idea would be to eliminate scoring from the game entirely and make it more a puzzle that yields to a solution, much like a crossword puzzle. The idea of the puzzle would be to use all of the letters in the keyword in every line and not to repeat using a word within the puzzle. (See my reworked solution for an example.) True, unlike a crossword puzzle, this would have a large number of possible solutions, but i rather suspect that one would not feel too troubled by that knowledge after solving one.
As for the length of the keyword, i do not know if there is an ideal length for it. Certainly it is difficult to imagine that it can be done with very short words or even those of moderate length. i had also thought that 19 letters might be a few too many in that every letter is more work and the time it takes to complete a puzzle seems a bit long to me.
I do not think that kadavergehorsamkeit worked because it is a German word containing many similar etymologies. Nor am i convinced that a 15 letter keyword would not work just because "snap beans no salt" seemed so unpromising. What i suspect is most crucial in coming up with words that will work is to have the right balance of vowels and consonants. With snap beans no salt, there are too few vowels and with the "s" and "n" both occurring 3 times, there are only 4 other consonants left to use. Regardless of length of word or its origin, along with Candy, i suspect that coming up with keywords that work would be a full time endeavor.