I wouldn’t worry about a pattern plate, in 50 years of shooting I’ve never known anyone do this. Gun fit however is very important, I have come to realise that my everyday knockabout doesn’t exactly fit me and is certainly making me miss more than I should, it has also left me with a big bruise on my shoulder and a sore cheekbone after a good session on the pigeons a few days ago.
If I use my ‘best’ gun, a sporter which fits me like a glove, I am a much more confident shot and rarely find myself thinking, “how the f*** did I miss that”, and certainly don’t suffer the beatings.
The only reason I haven’t used it regularly is that it’s heavy to carry around and in pristine condition, so I’m reluctant to put it down on the ground. That is about to change.
Don’t just buy the first gun that takes your fancy, try them for fit in the shop and if possible, also on the clays.
I am assuming that you haven’t done much shotgun shooting before, a lesson or two with a qualified coach may seem like an expensive outlay but will pay dividends for the rest of your life. I’ve seen plenty of shooters that have the worst shooting habits and consequently couldn’t hit a barn door at 20 feet, if they would just concede that they can’t shoot for toffee and get a couple of lessons, their shooting would be so much more enjoyable.