In all honesty you wont be needing such heavy weights if you combine pumping with it.
The vacuum hangers weak link is the attachment, usually the sleeve.
Mos has that fixed, I will be trying it myself in time once I get the new sleeves.
Another thing, that amount of weight you use will make your dick allot stronger, more resistant to stress as it has to adapt otherwise injure. Hanging more is not necessarily best.
If you really want to combine pumping with hanging, my take on that is to use a vacuum hanger with normal poundage's, you aint breaking records here, and already working off of pre-fatigued stretched out penile tissue, structures. Its not the "normal" state your hanging off.
When I get into a routine, which shouldm't be long I have the plan going along those lines.