The point is you can add ballast to the lighter plate but you can't subtract it from the SS plate!
I see you agree that a heavier plate is an advantage. It seems now your argument centers on how best to achieve this.
The sausage weight works only if you can find loose lead shot at your destination. Finding and purchasing loose lead shot at each dive site is problematic, and expensive.
A quick online check reveals that fishing weight sell for about a 1 dollar / ounce.
I've already debunked your suggestion to use gravel.
Using the sausage weight can bring the lighter plate to the same weight as the SS plate with no drawbacks.
The sausage weight needs to be secured to the back plate. Not a problem if you use a STA, but if you prefer not to use a STA, and many prefer exactly that, now you need some means of attaching the sausage. If you bolt it on the bolts will interfere with the direct mounting, and likely lead to tank rock.
If you choose to use the STA, you have to bring that with you too and you have again lost some of the massive, earth shattering, make or break the dive trip weight savings between a light weight and SS plate (~3 lbs.)
The sausage may also interfere with cambands that pass through the plate.
The loose lead shot required to fill the sausage needs to be purchased, over and over and over again if you are traveling.
Stainless Steel plates outsell al or other lightweight plates simply because they are a better solution for most divers.
My typical customer dives at home in moderate to cold water and travels ocassionally to warm destinations.
In most cases a single (that's one, not two )SS plate, and a single (again, one not two) wing can be selected that's a reasonable compromise for both.
Wings need to be sized for the most buoyant suit, and plate material is a function of required ballast, really pretty simple once you understand the process.
Look at a typical So Cal diver in a full 7mm wetsuit using a HP100 at home. If their suit is +22 lbs., They need a SS plate and Harness (~6 lbs) regulator (~2 lbs), empty tank (~2lbs) and 12 lbs pounds in a weight belt. If they opt to use the bolt on weight we offer (which can be used only with our SS plates) they end up with about 4 lbs in a belt. 4 lbs belts are easily managed.
Their rig will be about -18 with a full tank. If the rig is -18 and the suit can loose ~22 then a 26 lbs wing is a reasonable choice.
In warm water this same diver using a 3mm wetsuit and a buoyant al 80 will need about 8 lbs of ballast. The (same plate BTW, as in the
one the diver already owns and is already diving at home) SS Plate and harness is -6 and the reg is -2. The plate and harness is all they need. The
one wing they already own is larger than they need for warm water, but not so large as to be a significant problem.
Our diver, with the SS plate, will be in the water enjoying the exotic local diving while your diver is scurrying around trying to stuff 40 cu inches of gravel into a 10 cu inch sausage, after spending 1/2 a day discovering there is no loose lead shot available to purchase.
Simple is almost always better. Why take a BP&W and festoon it with STA's and bolts and washers and a sausages etc.?
To save a pound or two for travel? Most correctly see this as just plain silly.
Tobin