Not sure I follow your logic.
You want to prevent your subframe cracking, so you want as near to a solid mount as possible?
You need your mounts/bushes/suspension components to have some flex in them in order to disperse the energy that is being transmitted through your driveline/diff, rather than having it transmitted straight to your chassis/diff that you get with solid mounts or hard mounts, otherwise you risk warping/cracking.
If we are assuming that your wheel hop is indeed created from a bush not doing it's job properly, then it is more than likely worn beyond the factory limits and the bush is allowing more movement then designed. Replacing said bush with an oem bush that is within spec will be the way to address this.
If you have the majority of your suspension and bushes currently oem, then I recommend sticking with oem replacements. Oem parts are designed to work with each other. Yes using a polybush won't be the end of the world, but in my opinion unless you do the entire thing in polybush there is no point, as you start to upset the balance of the design of the car by throwing in foreign parts.
Also, if you look into the design of polybush sets that are available for the supra, they are primarily made only of edit: polyurethane, whilst oem bushes are a mixture of rubber + metal nevermind just had a look and they both have inner metal sections, dunno why I thought polybushes didn't, difference is then between polybush material vs oem rubber. There is a difference for a reason, and imo I'd take toyota's design over 'performance parts', unless we are talking about a car that isn't a roadcar