I also made a new countersink extender thing from some threaded rod. Allowed me to countersink the six outer rivets on the forward bulkhead. The instructions call for double flush rivets in these locations but the countersink stop is too large to fit in the flange of the bulkhead, so I extended above it.
11/6 2.0 countersink parts
11/7 2.0 countersink parts
11/10 4.0 made repair for firewall bracket
11/11 6.0 deburr, countersink, prime, dimple
11/12 8.0 riveting