Thanks for the appreciative replies. Some of you may wonder how does one find/buy such coins. So, to be clear, none were cheap but all except one were not expensive for what they are, but one has to move very fast (instantly) when such coins come up, i.e. make quick judgments on value. Of the three I'll certainly never get a better quality B den, Q quin or ROMA sest. I hope one day to get a clearer RRC 45 den (it was the relatively expensive one but it was very widely advertised and promoted so one day a better one may appear for reasonable prices: a VF-GVF say). An EF example of RRC 45 sold for $28,000 at the RBW sale. Not that that means much - EF Julius Caesar
denarii routinely fetch such prices yet can be found for a few hundred dollars in "collector" condition.
The Q quin was on a well-known auction site but the seller didn't even mark it as scarce, and those with just Sear or Seaby RSC would have no idea that it was very rare; it sold for a modest price. If you had the RBW collection
catalogue where a similar example sold for $700 you would have realised its rarity.
On the B denarius and ROMA sestertius I just moved very quick when I realised I could get them for fair prices. Very quick and decisively, no debating whether to ask for a haircut. To put my coins in context, a ROMA sest in merely fine condition fetched over $3,000 at the RBW sale. I paid significantly less for a VF-GVF example. And two examples of the B denarius, perhaps slightly nicer than mine, fetched over $7,000 each at RBW. I paid a small fraction for that at retail. In the case of the B and ROMA, hesitation would certainly have lost me these coins and possibly the only chance of every owning these rare types. I'll never have the financial resources that allowed a collection full of EF examples but nimble searches and quick decisions allow for a very reasonable 2nd division collection!
I may have left some budget collectors behind with the sort of single-coin prices one could buy a car for, but bargains are just as relevant in the $1000/$10,000 coin range as they are for $10/$100 coins. I'm an engineer on a salary, minding my pennies as much as the next.