FWIW, my experiences...
The three point belts work well, but they can pinch if your skin gets in between the ring and the elastic straps. A couple of cage makers add two point "handles" which can help. If you are wearing thin material, the 2 straps on your butt may cause noticeable "pantie lines". Normally after a week I find they are not needed, your body adjusts.
Normally I just use a thong, brazilian or half back cut panties - having a cut which goes in between your cheeks allows for the pressure to keep the cage pressed against your body with no pinching. Cotton I find works best & they need to have enough material in the front to hold & press the whole cage against you body (not all brands do). Men's thongs can also work if the pocket is small & snug enough (I wear small cages... ones that mainly just hold the glans, so many have pouches that are too big 🤷🏽♀️). If your body is being particularly pesky, you could use two pairs for more pressure & support...
These 3 cuts make your butt look peachy cute too.
If you want support & avoid cage contours to show through thinner clothing, padded cotton gaff thongs are good for this. It will not be flat as when tucking due to the ball trap & just causes a smooth inconspicuous compact small bulge. The "camel toe feature" on this type fortunately does not really work unless you are just wearing tights or leggings. The shorts in the pic below are very thin & pulled up... I don't think I had a cage on when I took the below picture, I don't remember.
If you are tucking or using them without a cage, it is good to go down a size, with a cage your normal size is probably correct.
You can find all the stuff above (except the cherry keeper ring) on ali, amazon, etsy, ebay.. etc etc.