Jim, to answer your earlier question, we have used a tow set up like what you described for nearly 20 years with a 17ft Arima with 115 HP Merc. (This is the workboat!!). It consists of the short line you mentioned and a long towline of up to 100 ft. However, the short line does not have the heavy steel ring you mentioned. Instead, we use a spliced-in stainless thimble (allows slip adjustment and less friction on the "working" towline) of appropriate size for 3/4 line. The towline and the short line are simply 3/4 braided nylon, as in anchor line, with a few net floats on it in case we ever need to pick it up. (Proper sizing depends on the job you want it to do.) The performance numbers are more than adequate for our application. The end of the towline has a spliced in galvanized thimble, to a galv shackle, to a 4 or 5 inch SS snap hook. Both the short and long lines are adjusted in length for the prevailing conditions and various boat speeds. We usually want it on center-line, riding slightly "downhill" on the second stern wave. That 2nd wave distance astern fluctuates with power setting, so adjustment capability is a must. This arrangement, according to my professional rigging engineer friend, carries only about 1/3 of the towing load on the short line (starboard cleat) and 2/3 load on the towing line, (port cleat). The towline also has some stretch to it, intentionally. Eventually, (years and years) the towline gets tired and looses the stretch and needs replacement, (once or twice in 19 years). (The risk in a non-stretch line is straightening out the snaphook and dropping the tow. Have seen it happen many times.)
We tow at 1600 to 1800 on the RPMs at 8.7 to 9.5 knots. The 1600 setting is the sweet spot for long cruising as it creates less stretch and wear on the gear. As you know, anywhere from home to Icy Strait, AK and back, one can find all kinds of weather and conditions. That said, we have never had what I would call an uncomfortable event with this set up. (I do confess to forgetting to re-cleat the short line or the towline when leaving a dock after using a cleat for a dock line. Can be embarrassing!) Normally, (90%?) the towline is out about 50 ft astern, or wherever that 2nd wave is. In very rough weather (10%?) it is adjusted out full length for easier towing. Chafe guards will give the lines longer life and I made up my own until discovering Chafe Pro; an absolutely superb product, (bought a spare pair several years ago and they are still unopened)! We NEVER EVER adjust the tow when under tension. Always in neutral with little way on.
Towline can be let out and recovered from the aft deck or the swim step. When recovering, (little or no way on) I throw on a life vest and prefer the swim step (unless in rough water). It is easily coiled on the step and it stays out of the way right there. (Fortunately, we have the wide swim step.)
Sorry this turned out so long. Hope it helps.