The Verve is the major event after the MAC in Chicago.
Harbor Springs has a fine regatta the week post Mac.
https://ltyc.org/ugotta-regatta/
also the Menominee 100 miler
https://www.mmyc.org/sail/100-miler/
The question is not the blocked keel but the ribs and bolts. Many old R 19's have had rib and bolt replacement. Find out the history of storage and maintenance then get someone familiar with R 19's to survey the boat and equipment. Are the fittings old or upgraded? Are the sails old or...
Ask each sailmaker about their experience with your design. What is the brand of your mainsail? Go with the sailmaker that made your main if there is a match.
The 38 under PHRF is best in moderate and heavy air. Weakest in close reaching because of the small jib. The 41 is best in light and moderate. Strong in close reaching because of large foretriangle. The 38 is much easier to sail. Forget the 40 if you can get a 38.
I patented a cam cleat the pivoted in two planes in the late 1960's in the US.
I saw it in action on a large cat in the 1970's. Because the market was so small I did not prosecute the offenders or try to commercialize it myself.
On the cat it was set to release at 14 degrees heel.