Size wise, I think you could trim those templates down about an 1/8-1/4 of an inch and they would work for you.
Also you are going to need to bring the collar plate up a touch, you want it resting right in front of your collarbone. Which means you will more than likely need to modify the chest plates so you don't stab yourself with those corners, when you move your arms. It is always best to get the collar in line first and then work down from there. If it means your chest diamond is up a bit, that is no big deal. We are all shaped different after all
and that means lots of tweaking to hone things in. Try being the templates up half way between where they are now and where they were in the first picture and you will be spot on!
Another option would be to switch to the Ronans Templates (which can be found here- http://mandalorianmercs.org/forum/index.php?topic=73517.0
) they have a longer V shaped collar which allows you to keep the curve of the chest plates in the right spot without the need for modification and doesn't leave you will the big gap you have in your collar coverage right now.
Keep at it vod!