So first off you are right your plates are too large. You shoulder bells however are fine size wise.
However your collar could stand to be just a bit smaller, and your chest plates and thus your ab plate really should be a bit smaller. I would take a quarter inch off from the plates and go from there.
As for spacing you want to use the rule of them you want enough space between your collar to chest plate and chest plate to ab plate that you can fit your thumb. It is also helpful to remember the lines you are working from you want the inside of your collar plate to side along the line of your collarbone and you want the bottom of your ab plate to side right above your navel. Once you have those positions fixed it is pretty straightforward to insure that your plates are both the right size and that they are spaces right.
Another thing to keep in mind that it is very very common to have to use more than one size of templates for your plates. I have known people that have used four or more different sized templates to get patterns for plates to fit their body.
