>
> as sweet as 'normal' apples?
not so much and not so juicy

> how does the size of a crab apple tree compare to the normal apple tree?
It depends you have as many crab apples varieties than you can imagine
,they come in all sizes but generally they are around the size of a ping
pong ball , some varieties are almost inedible others can be more flavorfull
and sweet than  normal size apple ( that are in fact anormal ) , but
generally they are more tart and astringeant
jean-claude