bottom leaves turn yellow and you just cut them off ime, theres no need to really cut yellowing leaves. they will get used up until theres nothing left in them and shed naturally. cutting puts stress on plants, and if its unneeded then why do it? just my two cents.....
PUT THE SHORTER PLANT ON SOME KIND OF STAND TO BRING IT UP TO THE HIGHT NEEDED. THAT SHOULD SOLVE THE PROBLEM. GOOD LUCK!