All examples should work as is. If you have problems with any of them then let us know.
Iterative translation/rotation works well for positioning in 2D, but in 3D but it is just too tedious (you need to move the object and continuously evaluate in multiple views if its position is optimal).
Instead, it is recommended to mark your targets (and optionally, regions to avoid) with markups points/lines/planes and/or segmentation. From these inputs, optimal treatment plan (such as ablation zone shape and size) can be computed automatically using a simple logic. You may then review the plan and make small adjustments.
There have been a number of thermal/laser/radio ablation planning systems built on Slicer for spine, liver, prostate, etc. so if you have specific questions about how to implement anything then we may be able to help. For example, using SlicerRT extension, you can visualize not just a sphere but thermal dose in 2D and 3D as isodose lines/surfaces, compute dose volume histograms for target organs and organs at risk, etc. Using SlicerIGT extension, you can implement real-time navigation of the ablator, optionally using image guidance (CT, MRI, live ultrasound, etc.) and do all the necessary patient registrations and tool calibrations.