Dan , here is my 2 cents / IMO .
 The French stock design and the English stock designs are different do to a different style of shooting .
As Mario mentioned . The NW gun can have at times very little drop  .But not always .  The comb is also very flat across the top , which IMO also takes some getting used to .
 But the reason they are that way is that the English style of shooting a gun  was basically how we shoot today . IE you  step into the gun as you shoulder it . Just like you would a modern rifle or shotgun .


With the French designs , they often “depending on the maker “ have a lot moor drop to the heel and a more rounded profile to the  nose of the comb . This calls for a much more erect stance  when shooting .  IE your head is up  not forward and down .
  Thus if you have large cheek bones and  try and lean into the gun  with your face forward , the  rise in the comb often will end up recoiling into your  cheek bone .
  When I learned and accepted that  difference and thus began shooting my de chase , with a more erect stance ,  the gun not only became much more comfortable to shoot but my accuracy also improved greatly  
De Chase 

 Now note I said depending on maker .
 The reason I say that is that not all French designs have that roman nose to the comb .
 What the largest % that I have seen do however have in common is a greater drop from the nose to the heal then on English guns .
 While this isn’t a De Chase  you can see what im getting at 

 Now as to the ups and downs .
  The plus is I  can reload much quicker then  I can a rifle . Also I have the ability to shoot either shot , ball or both . I actually to a very nice cow elk some years ago while hunting grouse , because of that ability . Literally I saw the herd coming down the ridge , was able to  quickly pull the over the shot card , dump out the #7 ½ that I was loaded with . Drop a ball in and  push the over the shot card back in  and still have time to make the shot .
As to a draw back . I would say that would have to be accuracy at ranges  past 75 yards .
 However that also may not be an issue  while hunting . As you know a lot of times out  harvest range back here is  rather close . As such  , frankly  I see no difference between  how accurate my smoothbores are  compared to my rifles at those closer ranges .
 Now one thing that I have had a problem with is heat waves coming off of my smoothbore barrels . Especially the longer barrels . They distort your sight picture much more then they do on a rifle with an octagon bore  when you out shooting on hot days .
 Now his is just my opinion but considering you build , you may find the NW gun to be rather small in stature for you . But at the same time  your probably going to like the larger  trigger guard . With your height and size , if you do go with a NW gun , I would find someone who would build you one  that’s based more on a early design with much more drop  then those commonly seen today. IE something that’s alittle more then  the original  I showed in the first photos .
 Now the other thing is price .
Doing a French gun correctly , is much harder then doing a NW gun . Thus they cost more .
 But the plus is that they were also done “depending on the model you chose “  in degrees of very simple , to modestly decorated , all the way to very extravagant gentleman’s guns.
 Not so with the NW gun  which even in so called chiefs grade , is  not  very ,,,, how should I put this , gentelman ‘y   LOL 
 But then they don’t really need to be .
 Now myself I have owned  several NW guns and more then a few De chase .  I prefer the French designs . One of the only things French that I do care for .
Let me also put in little plug here .
  I don’t know what price range your  thinking of  or  time fraim . But  if your  thinking of a frenchy and  of something  more then the run of the mill trade gun or  De chase , give me a call . I would most certainly  enjoy entertaining the concept  and challenge of building you a fine piece.