My concern is that if I put through one large transaction on my CC
once every 3 months.
I'd like to provide an answer to just this concern. The accepted answer covers the real issue, the larger issue, that small swings are meaningless over time and you should just be aware before applying for credit.
As someone who likes to know the smallest of financial details, I began to monitor my score and found that if I wished to game the system, maximize my score, the real issue wasn't spending, it was payment timing.
In other words, I would make a large payment to credit the account the day before the bill was cut. I managed to pin our scores to 850 via this method, and when applying for a renewal of my HELOC, after retirement, was pleasantly surprised to hear the agent mumble "holy crap". Huh? She then said,"Oh, sorry, I'd just never seen a couple who both had 850 scores before."
That said, one of my cards changed banks, and while the billing cycle never changed, the reporting cycle did. The bill gets issued on the 15th, but the balance on the last day of the month is what started getting reported. One month of a huge drop in score, a lesson learned, and now I pay the card twice each month, on the date the payment is due, but again on the 30th to zero out the balance reported.
All this effort is not needed for anyone who doesn't really care about those last few points. It's easy enough to get the reported balance to near zero ahead of an important event, again, as noted.
Note - there are free services that offer a simulated credit score, Credit Karma among them. It offers an easy way to see when your accounts last reported your activity. I get my FICO score from other sources, but while the score is more accurate, the supporting details are lacking. For those who are a bit obsessed, it takes a few sources of data to provide the whole picture.