Digit -

Your heading down the right direction. The names of the scales isn't important, it's the understanding and usage of them that counts. Like SLY said, there is alot to be learned from analyzing chords and scales. For example take a major scale and play it over a major chord. It sounds good because the scale is compatiable with a major chord. Move up in the understanding by taking a E minor 6 chord, now which scale works better over this chord?? Well, the melodic minor scale. Not the minor scale because the 6th in a minor 6 chord is natural. In a minor scale the 6th is flat. So it's less compatiable. The 6th in the melodic minor scale is natural. This understanding is very beneficial to a player, especially someone in your position cause it only helps with what comes natural. Don't think of a scale by it's name but by it's pattern and how it relates to a chord and/or chord progressions.

Pantallica -

Try not to think of it as "the right way" or "the wrong way". This may disappoint you but there is no correct way to play a (perfect)solo. You can play over a chord and/or chord progression in so many ways that the end result will leave you with chromatics. The key is to understand how each scale will effect a chord progression and what kind of sound you will get by using a certain scale. This can only be achieved by practicing scales over chords. It's just something you have to learn on your own. But to answer your question, you can do it either way. Play a scale over a chord progression or play a different scale over each chord in a chord progression or a mix of both. Just make sure to match the root and that the scales are compatiable with the chord(s). To check this all you do is look at a chord like a G major chord and see what notes make up that chord. G, B, E. Now any scale with the root G and the notes B and E within it will work. To check to see if a certain scale will work over an entire chord progression, just look to see if the scale contains the chords in the chord progression. (i.e. If you have a chord progression like D7 - Am - Gmaj, you should know that the G major scale will work cause all those chords are in the key of G major (G major scale).)