HI erico, about the ligth, you have in mind this:
If you have the target in the 0,0,0 the ligth always lock to this point, if you want make circles over and object you have to use cos and sin, in x and z or x and y, depends how export your software to GLbasic, in 3d Max not it´s equal than AC3D or Blender, anyone have her how world coordinates system, or mode to make it internally.
Yes if you put the lights degree cone to 360, you have a spot light, in principle affects all the scene, because light "simple" don´t have range and don´t have intensity too.
ok, if you want develop only for PC, use a library made by Gernnot, it´s in some part of 3d thread, have a lot of more commands, and it´s very complete, but in mobile devices I think don´t works well, I don´t try.
If you permet I have a little trick, so Glbasic 3D in devices mobiles don´t have too much coomands, I try the make ready the model always in the editor, always I export a backed texture, whit lights, normal maps, and of course we don´t have a parameter for shinnes specular

, but I tri to make things in 3D, and the quality it´s good, but we have to put more effort in the 3D suite.
Warning, if you make a backing texture, if I don´t rebenmer bad, you use LW, be careful whit the channel map of the texture, in Max in example, I have to put the channel inverse, when it´s 3 in material, in backed it´s 1.
Another point, and this it´s only for advice, for me the best tool for texturing, in low poly I think it´s a most important part, I use Bodypaint,this it´s a module of Cinema 4D, like photoshop but you paint over the model, or un the unwrapped mesh, and another Sculping tool very very good, and not too much expensive, professional cost about 300$ and educational cost about 99$, it´s Coat 3D, it´s like Zbrush, but too much simple, and make thing awesome, and well it´s another genius like Gernnot, 3D coat it´s male by only one Ukranian men, well mother Russia always was the better in Maths...

PS: I think we can use this thread for sharin impresions about 3D in Glbasic, not too much people use 3D, and can sharing tips and tricks, waht do you think?.
Iván J.