Add a symbol to the symbol library

A certain FDOT district office prefers the term "SURVEY LINE" to either centerline or baseline and I have been happily typing that in to my DGNs. My latest project however, will be very "text intensive" with multiple survey lines. In the interest of reducing the amount of typing and the amount of text in the files/ sheets. I was wondering if it would be possible to create a symbol for the symbol library that could be placed in the word processor favorites drop down, that would made up of the letter S overlaid with the letter L similar to the baseline and centerline symbols? Using a cell would be too cumbersome; and the abbreviations "S/L" and "S.L." aren't visually appealing. Can you help?

I using the following:

FDOTSS4 MR8 (Version 01.08.01) (Right of Way menu)

Power GEOPAK V8i (SELECTseries 4)

Windows 10 Enterprise Version 1803

HP Z240 Intel Core i7-6700 CPU @ 3.40 GHz 64-bit os, x64-based processor

Thanks for your time and assistance.