Never stopped you before
I've done it but it's not always successful in improving the seal. I really think you should try out the VE thick donuts from the VE expack. My mistake earlier I called them hiegi donuts, those are different and not as sealing IMO. Get the VE ex pack for its thick donuts instead of hiegis!
Hiegi donuts still have their time and place but if I ever need a thick donut foam for pk shells I always choose VE expack donuts first. They are almost bowl shaped (they have more of a structure than most foams thanks to the dense foam used).
Compared to full foams you will get a slightly more clear midrange and the imaging is more centered because of this but the seal is the important factor here so if it seals better for you the bass response will be improved over full foams.