Well, you asked for constructive criticism, so here goes;
In general, it's a very nice design, and period correct. Simple, but elegant, and not overdone.
Now for areas that can use further attention;
You have a lot of flat areas and elbows in your curves. They need to flow. One way to spot them is to turn the carving at various angles and see if EACH volute has an evolving radius (going up and down the curve). Look at the curve in totality, and then in incremental sections. All 3 of your major features have flat spots and elbows in their curves. Don't go any deeper.
You have a lot of inconsistency in your toe line decoration. I can't tell if this is supposed to be raised or an incise. Your tools are dull. Try using a half-round riffler file on the convex portion. The long shoe and bearing surface will again even out your curves. It will also even out the "digs" from your tools as you transition from softer wood to harder wood.
The toe line accent looks odd in the margin as you approach the butt plate. It seems to sweep upward creating a greater margin to the toe line. It's odd because these features usually either increase / decrease their margins in one direction or another, or remain constant. They typically don't have an "S" shape to them. Yours does.
In general, you are in too much of a hurry to get it done, and your tools appear to be dull. Slow down. Sharpen often. That butt carving should take you upwards of 30-40 hours to do, and do a good job at.
Your cheek rest accents can similarly benefit from the use of a file to smooth them out.
Some of the incise curls have flat spots too. Those are trickier to smooth out, but it can be done by taking some off one side and then the other as the curve evolves. Start your incises with the smallest of push-carving tools. That initial scratch won't be but about 1/128" wide and only a couple thousandths deep, and then expand it to full width and depth (between 1/16" and 1/8" depending on the feature) by widening the appropriate sides to take out the elbows and flat areas.
Where it comes time to smooth out your base plains use scrapers and backed / blocked sanding tools. You should use what ever the longest soled instrument you can muster to avoid a "faceted" look to leveling those base plains--TAKE A LOT OF TIME on this phase!
Remember, the most important tools in carving are your pencil and even more so, the eraser.
This is all offered in the spirit of trying to constructively help, not nit pick.
off to a great start
