Buy or make yourself a chest harness for your radio. They're quite common and made for the purpose.
I'm not sure why you would carry a radio. They're really only useful for talking to your friends who also have radios. Trying to get somebody to hear your call for assistance will be easier said than done.
I have used a SPOT tracker for years. I use it all the time paragliding and sometimes kiteboarding. I might start to use it more now that we are doing longer foiling runs.
If you need to communicate you can press any one of two custom messages. If you need assistance then you also have one help message (to your friends or family or whoever), or send an SOS call to the emergency services. Even if you can't press the button, your friends watching you can work out if you are in trouble and give assistance.
The Delorme trackers are better because you can send and receive text messages anywhere in the world. They are a lot more expensive to buy and run than SPOT.
Ideally you could have both a radio and a tracker.
PLB/EPIRB are almost useless for most recreational purposes. They just sit there and do nothing year after year then you throw it away. The other side is they are often triggered by mistake and the emergency services are called out for no reason. You can end up with a bill for that.