To keep the costs of my fretless banjos down I use tacks to secure the rawhide heads. The costs of handcrafting or acquiring brass period correct 19th-century fittings, adjustable rods, J-hooks and rings would be prohibitively expensive and would at least double, if not triple, the cost of my instruments.
Sound sample from a fretless 12" Minstrel Tack Head Banjo
With rawhide banjos, tension rods and rings are mostly cosmetic. One of the reasons that some people think an adjustable head is better, is that it gives them the flexibility to be able to adjust the head when the cool or damp begins to relax the rawhide.
Adjusting to Temperature and Humidity
In damp and cool weather any instrument made of organic materials like wood or hide will naturally adjust to the environment. In hot dry weather most of these instruments will sound brighter or sharper in tone. In the cool or damp they will sound slightly mellower or even a little bit muted. The movement of the rawhide also affects the string action, but this is just part of their charm.
If you have the ability to tighten the skin in the cool and damp to make it tighter or brighter in sound, you had better be prepared to loosen it back again if the weather changes to a dry sunny day or you could run the risk of either splitting the rawhide head or damaging the wood shell on which it is mounted when it shrinks back.
With a tack head banjo the hide is put on damp and shrinks back to an optimal tension in the full 360° circle. In cooler damp weather the rawhide head will relax slightly, but when returned to the sunshine or a warm dry environment, in very short order it shrinks back to its original tension, with no danger of harming the wood shell, the gourd or the hide itself. In other words, the tacked on rawhide head naturally adjusts itself to the environment.
Use Variable Height Bridges
Rather than tighten the tension on the rawhide head, I use a trick used by the old-timers. By keeping two or three different height of bridges on hand, I am able to insert a taller bridge as the head begins to relax and then switch back to a lower bridge as my environment becomes warmer or dryer.
As a performer, I have had many opportunities to play side-by-side with owners of adjustable head fretless banjos in the Sweeney or Boucher style and they use the same technique as I. My 14 inch tack head banjos are actually louder and maintain a more mellow tone as the humidity rises and the temperature drops. My 12 inch banjos play with about the same tonal qualities as the Boucher replicas. (The big difference is that they cost a lot less.)
I have yet to see any musician with an adjustable head banjo actually make a head tension adjustment during a performance. Properly adjusting a drum head for optimum tension is a finicky business taking a fair amount of skill and time. I have talked to many adjustable head banjo owners who will admit that they have never adjusted the tension on the head of their banjo.
What I am suggesting is that having an adjustable head banjo creates as many problems as it solves. You are likely to have less problems with head tension or potential damage if you simply leave the adjustments alone. In this case you have the functional equivalent of a tack head banjo.
Mostly a Cosmetic Judgement
Cosmetically, these adjustable head banjos do have a different look. If what you are looking for is a replica banjo of a Boucher or a Stitcher, then appearance is as equal a consideration for you as is the sound. If on the other hand, you simply want a fretless banjo with a correct period appearance and tonal quality, then a tack head banjo is definitely a more economical choice.
I still have and play my first 16 inch calabash gourd fretless banjo. Over the last 20 years, it has accompanied me to countless primitive camps, canoe trips and even snow shoe treks. I have never adjusted the head and it still sounds great! If the hide gets too damp and relaxes, just a few minutes beside a campfire or in the morning sun and it is tight and ready to play.