Forgive me if this is well known on FT. I'm a newbie and didn't find this with a search, but you can use the credit monitoring service freecreditscore.com to simulate what effect more hard inquiries will have on your credit score.
After applying for 3 cards in 2 months (Chase Sapphire, 2xCiti AA) for myself and 4 for my husband (one oops, 2xCiti AA, and Chase Sapphire), I checked free credit reports (annualcreditreport.com) and signed up (temporarily) to freecreditscore.com to get a feel for my credit score.
My score is considerably lower (35-50 pts) than it was last summer because I stupidly, stupidly cancelled 2 credit cards dating from 1996 recently before I realized the importance of credit age. Did I mention stupid?
It was easy to tell that my recent credit apps hadn't caused the decline, tho, because the freecreditscore.com site had a simulator where you can test the effect of different variables including the number of hard inquiries on your account.
In my case, Experian showed 4 hard inquiries and gave me a score of 796. If I adjusted the number of hard inquiries to 0, my score would jump to 808. If I had 7+ hard inquiries, my score would drop to 787.
I've read many places the estimate of 6 pts per hard inquiry. In my case the simulator showed I had lost 4 pts for every inquiry, and would lose a total of 9 more points (avg 3 per) for 3 more inquiries.
Hope this is helpful to other newbies.
Akp
PS - note that you can immediately cancel the monitoring service and there is no charge. I think you have up to 7 days to cancel.
Your credit scores are high enough so that canceling those cards as you did should not bother you at all.