hi!!!need help

hey everyone!!! iim counfused about training with weight vest and with no vest at all... im doing a routine of weights on mondays and thursdays, and jumping + plyos on tuesday and fridays.... im curious if i should add weight vest on jumping exercises to be able to jump very high...

jumping - squat jumps 2x60 +5 everyweek, tuck jumps 2x24+2, chair jumps 2x 30+5

plyos- drop jumps 2x6-34" height, box jumps 2x8, reactive jumps 2x6-34"

.....it says in some sites that all u need is quality not quantity in jumping and proper form is required, but other sites says that additional resistance(weight vest/ankle weights) can give u a greater gain....im sure in plyometrics that it should be only bodyweight, im not sure in jumping though....so which one is it???

if it should be best to add weight vest on jumping, is it okay to go for jumping+weight vest, and plyos(bodyweight only)??....if im having too much weights(vest) w/ jumping high reps is that it causes some knee problems like before...i only currently have a 25-27" vert jump....
tnx