The
OSL isn't bad. It has a nice, tight gradient, suitable for a simplified and exaggerated effect. Remember, though, that the light source is always brighter than the reflected glow. Using a more subdued red around the eyes and the brighter red-orange for the lenses would be more convincing.
The freehand isn't that bad, either, especially for a first try. The lines wander and change thickness in a few spots, but not terribly. Believe me, you could've done
much worse. No matter how much you (dis)like it, you're definitely right in thinking it's worthwhile experience, at least. For the sake of expediency and ease, it might be better to just buy the bits, but I wouldn't give up on freehand, entirely, even if you just practice doodling by brush on primed scraps.
The weathering, I think, yielded the weakest results of your experiments. On a few areas it worked reasonably well, like the brown on the feet, but for the most part, it just made the paintjob look rough. If you're looking for alternate methods, I highly recommend you search for "sponge weathering" or "sponge chipping" tutorials. It's dead easy, at its core (granted, you can take things to the extreme and highlight individual chips, etc.), and yields far more realistic results. The only method I've seen that does it better is the hairspray method, but that's a bit more involved and more or less necessitates using an airbrush.
There are a few unrelated areas that could also use work, but they may have just been rushed or glossed over, since this was a test model. I won't bother picking those nits, in case you saw fit to leave them, yourself.
