If you're really getting compression wicking, it wouldn't happen with PUL. I think the problem may be not enough absorbency up front - I usually fold any doublers or inserts in half, and put them in the front, so there isn't all that butt-bulk that isn't being used.
A wool soaker isn't going to be much better than a fleece cover in terms of compression wicking - wool depends on the diaper having enough absorbant material to slow down & disperse the stream of urine in order to work properly, as, I suspect, is also the case with fleece covers.
A wool soaker isn't going to be much better than a fleece cover in terms of compression wicking - wool depends on the diaper having enough absorbant material to slow down & disperse the stream of urine in order to work properly, as, I suspect, is also the case with fleece covers.