The only real way of doing authentic old fashioned pre-60’s initials is to do it the old fashioned way with old fashioned tools. Primarily, a pencil and paper and for Old English, a ruler and square. A divider or compass with a pencil lead in one point is handy too.
There’s no secret or trick to it, just do a search for “Old English images” on the 'net, find one you like, print it out and start drawing. You will find that doing Old English style lettering can be the most difficult of all lettering styles as it requires absolutely parallel lines and perfectly right and 45 degree angles or it looks like, well, you know. Unlike the invisibility of slight imperfections in most decorative engraving, lettering, especially Old English, displays even the slightest errors in spacing, shape and placement. The human eye has become accustomed to seeing lettering and will instantly spot the smallest deviation from perfection. Old English and similar styles just make flaws that much more apparent.
This is a design that a client and I designed for her husband as a surprise anniversary gift that might fall under the classification you mentioned. It is a variation on a design in J. M. Bergling’s book, Art Monograms and Lettering. We loved it, he hated it. Keeping true to my word that you love it or you don’t pay for it, he and I designed an oval shaped signet ring with a more traditional vertical script. It took me about ten different drawings until I finally got what he wanted. I’ll post that next.