My First Coat - a Corpulent Coat

I am starting work on my first coat. Following Rory's draft CT23 - 0" corpulent Draft in his Pattern Drafting for Bespoke Menswear, I have taken my first tentative steps making a toil while I await the arrival of the trimming packages. I intend this to be a documentation of the project as well as seeking some advice and suggestions along the way.

For reference, the measures are as follows:

Height: 5'10"

Head Unit: 8 1/2"

Chest: 50

Waist: 52"

Seat 49"

Depth of Scye: 10"

Proportionate Scale: 25"

Disproportionate Scale: 22 1/2"

Coat Length: 29 1/4"

Half-back 10 1/4"

Posture: stooping

In terms of making-up I am following Rory's course: The Making of a Savile Row Coat, and using the standard grey included in the Dugdale's Trim Pack, or otherwise the Super Fine Merino Wool Royal Pearl Collection Made In England Slate Grey, because it is fairly affordable at just over 26AUD per meter - its almost impossible to find pure wool suiting in Australia, and that which can be had is rarely under $90 per meter or is of doubtful origin and quality.

In drafting the pattern I first drafted as per CT23, and then traced that off so I could keep an 'original draft' to revert to if I lost my way. On the copy I made the following alterations:

1. The side-body conversion;

2. Stooping posture. 

Following the above  I made-up a trial in plain calico.

The first toile came out okay with only minor adjustments needed to the shoulder length and a little taken out at the side and centre-back. about 3/4 of an inch total which I assume is probably within range of variability found with stretching and shrinking plus a good meal or three. It was too messy to take photos of so made another cleaner one, taking out the excess the was identified in the first.

I am conscious that this is calico, and so does not behave the same as a cloth with respect to drape, and has a tendency to cling a little more to the clothes underneath, even so there are some significant fitting issues that I am curious about correcting.

The first is the folds of cloth forming around and under the arms (circled in blue) and some folds running over the ridge of the shoulders and pointing towards the front of the armscye (circled in red) . I'm am reluctant to cut a deeper scye, and wonder if I have cut the arm scye too close at the front? It is an issue on both sides and this may show a better image:

At the hind-arm I'm wondering if that might form a drape when made-up in proper cloth and offer the necessary forward movement of the arm?

I am reasonably happy with the back mindful that as made-up there are no vents and no stretching or shrinking that has gone into this.

Making-up the toile presented my with my first question on making-up: how to go about the dog-leg cut? In the drafting video Rory mentions starting at the point of the dart, but no-mater how I approach it, I seem to end-up with a pucker along the 34-H line below point H.

Some practice runs at sewing this in Calico have thrown-up a few questions:

1. What is the point of the dog-leg in the chest dart? Would the necessary room in the lower chest and suppression along the bridle-line not be provided by a dart that simply extended on the line 20-H and out to the edge of the lapel?

2. How to sew a dart with a corner in it? I can't tell if my dart-sewing skills are not advanced enough, or if I have missed an important aspect of sewing it.

3. How much, if at all, should one fuss with a toile in calico before moving to making up in wool? And might I expect some of these issues to pull-out once I add sleeves?