Just to close the loop on installing brake master cylinder. Perfect success with many thanks to Pat, Pawell66, and Wallace. Attached are some photos. I was probably in overkill mode but with Pawel66's suggestion I took a spare reservoir and discovered that a 3mm diameter tube fits perfectly in its openings. Vacuum tubing from a subsequent model filled those openings. I then installed the 3mm tubes into the reservoir with brake fluid, removed the plugs and screwed in the brake lines. Can't imagine there was more than 5 drops of brake fluid total.
Thanks guys, you're the best!!