A display riser should make a figure easier to see without making it harder to support. Choose it around the figure's base, weight and viewing position. A tall platform that hides the front row or leaves a base overhanging has not solved the display problem.
Lay out the rows before buying
Make paper footprints for each figure's base and widest accessories. Place them on the shelf, then view the arrangement from where you normally sit or stand. Mark which faces disappear behind the front row.
Raise a paper silhouette to test the height needed. Do this with lightweight mockups, not a collectible balanced on stacked household objects. Check the remaining space above the figure, including access for removing it.
Match the platform to the load
Read the riser's stated load capacity and dimensions. The whole base should have stable support without rocking. A transparent appearance does not tell you whether a platform is strong enough for a particular statue.
The shelf below still carries the total weight of the riser and every item on it. Follow the furniture and platform instructions rather than assuming that several small objects cannot overload the shelf.
Keep the arrangement readable
Use fewer height changes if the shelf already has elaborate poses and effects. Leave a visible gap around the main character's face and silhouette. A back row need not be equally prominent if it is deliberately supporting a centerpiece.
For Super Saiyan Sphere statues, record the selected figure's base size and total height before choosing a riser. If those details are unavailable, confirm them first. The platform is an accessory to the figure, so let the actual object determine the fit.
Related guides
How to Arrange Anime Figures on a Small Shelf · Can Your Shelf Support a Heavy Anime Statue?