This suggestion will be controversial....
Take your two old tanks to a Blue Rhino (or equivalent) dispenser. They will accept your old tank on trade. You'll get a reconditioned new-style tank filled with Propane for about $20. The gimmick is that Blue Rhino only fills tanks about 75%. Still, this is a pretty inexpensive way to trade your non-compliant tanks in on two reconditioned tanks. You can then get the Blue Rhino tanks filled in the future or just swap them out for pre-filled tanks.
I did this with an old style tank a year ago at a Walgreen's. I told the manager this was an old style valve and she said it didn't make any difference to Blue Rhino, they just replace it with a new valve. They did want the tank itself to be in fairly good condition though.
Hope this helps!
Alfred
2005 Sightseer with Workhorse, ReadyBrute Elite towing 2003 Honda CRV
Map below shows states where we actually camped.....