I'll answer your queries in order ...
I will be using Vcarve at times for small items and have found that during text carving the depth is only a thou or less. For example I would like to make the min depth .010" and max depth something proportional. I'm using a 90deg v-bit, .125 diameter.
For VCarving, the depth is governed by the distance between the vectors you are cutting. If we take the simplest case of a rectangle and the 90deg tool you are using, as the V-Bit tool is moved along the 'center line' of the rectangle, if the rectangle is 0.1" wide the tool would have to machine at a depth of 0.1" to cut the width of 0.1". As you have noticed, for very thin vectors this will lead to very shallow engraving. You could force the program to cut too deep, by using the the "Start Depth"
field on the Create V-Carve Toolpath form and setting a value of say 0.05". However this will overcut all areas
by the same amount so have a careful look at the simulation to ensure that the results will be acceptable. Generally, if you are doing very small or detailed work you would need a much narrower angled tool (60 deg down to 20deg) as these tools will cut to a much deeper depth for a given width of vectors.
Secondly what makes Vcarve decide when to do an area clear, at times I would like to just follow a line at a depth rather than have it clear the area, like on the Santa sleigh, it clears out the hole sleigh. Is it possible to just cut on the vector line?
If you select the Create 2D Toolpath
icon on the toolpath operations page (the third icon along, after the vcarve toolpath icon) you have the option to machine the selected vectors using a variety of strategies ...
Pocket - also called area clear, will machine a pocket between the selected vectors at the depth you specify
Outside - will profile outside the selected vectors to the depth you specify
Inside - will profile inside the selected vectors to the depth you specify
- this is the option you are looking for. This will simply follow the vectors at the depth you specify using your chosen tool
However, for cutting out Santa's Sleigh (though it may be too late now
) The Outside
strategy would usually be used, this is demonstrated in the accompanying tutorial video and file.
I hope I've interpreted your queries correctly and that the the above answers your questions, if not just keep asking!