A little progress with MAME Analogue...

[Gradius]

After many tests I've finally got it! I have control with both usb mice in lightgun games. I opened up the 'input this game' menu and remap the lighgun x y to the mouse input. By default it's mapped to joystick 1. The strange thing is that I cannot remap lightgun x to mouse up, for instance. I mean: I click lightgun x and then move my mouse up so as to define the control, but no input is registered. However if I click mouse 1 button, it's registered. Even more strange is the fact that, if I do not remap controls to mouse (button 1 or 2 click), the crosshairs don't move at all with any of my mice. As soon as I remap lighgun x to mouse 1 button, that axis of the crosshair begins to work. Same with y axis. Same with both mice I've finally got it working, but it's a tough task. So as not to interfere with fire, I remap again lightgun x an y to a keyboard key. Both mice axes keep on working. I remap button 1 and 2 to the mouse buttons. This works for both mice and both work independently. How could I tell MAME that I wish the same config with mouse controls for all games using mouce? It would be a pain to remap all axes so as to enable my mouce control and the remap them again to a key, etc etc. This happens with all lightgun games: no control at all over the crosshairs until I remap lighgun to a mouce button.

[Gradius]

Solved! At last! The problem lies in the default controls. I scrolled down until I reach lighgun controls in input general. I remove lightgun x and y for both players, which were associated by default with joysticks and keys, and now everything works perfect: control over the crosshairs with both mice from the very beginning. Great! I think I'm going to compile the source of MAME Analogue together with my build of MAME32.