String height/size on a Guild acoustic

Q: I recently bought a Guild GAD-30R acoustic. I tune it in Open D, and play about half the time using a glass slide. My problem is that the strings appear to be too close to the fretboard. I say "appear" because I am primarily a keyboard player and only recently started playing guitar. I'm still learning about guitars. I have a couple of questions...

1. How hard is it to raise the strings a bit on this guitar?
2. Can I raise the strings without wrecking havoc on how it sounds?
3. The strings that I have "tuned down" for OPEN-D seem a bit too floppy...would I be well advised to increase the size of these strings a small bit?
4. Last but not least...this sounds like something I need a professional to do...so how much might you charge me to do this?

Thanks, Will

A: There is a formula for calculating the pitch of a string. It relates length, weight and tension. When you go into D tuning the length of the string stays the same but the tension is less. You need to compensate by raising the weight of the string. Heavier strings would give you more power and be less floppy.
The common complaint about the action being too low is that the strings buzz against the frets. You don't mention this. Raising and lowering the action, within reason, does not effect the tone. It sounds to me like an action set would cure your ills. We straighten the neck, level the fret tops and set the height of the nut and saddle, and set the ramping from the saddle down into the pin holes. All new guitars need adjustment and they need to be readjusted periodically thereafter. We charge $65.00 plus new strings. Are you within driving distance of Lawrence, Kansas?

Steve Mason