Are multi-megaton antimatter induced fusion explosions theoretically possible?

Are multi-megaton antimatter induced fusion explosions theoretically
possible?

I just finished reading this research about antimatter induced fusion and
thermonuclear reactions. And one conclusion I could make is that very
little mass of antimatter (in range of micrograms) is needed to initiate a
fusion reaction in lithium-deuteride fuel.
Also, in page 14 in this PDF file, there is a theoretical design of a
1-kiloton antimatter induced fusion bomb.
Now, I actually have 2 questions. Firstly, 100 grams of lithium-deuteride
is used in this theoretical 1 kt design. But according to this, 100 grams
of lithium-deuteride should yield 6.4 kilotons not only 1 kiloton, so is
there any explanation of this ?
Secondly, since I seem to find only low yield designs of antimatter
induced/catalyzed fusion bombs, a doubt about the feasibility of larger
yield came to my mind. So, if a single kiloton fusion reaction is feasible
with a certain amount of antimatter, then should we consider fusing more
fuel with even more antimatter feasible too ?
Note : I completely understand the difficulty of making, handling and
storing antimatter, and I am not saying this thing is going to be made any
time soon. I am just curious about the physics part behind it.