Some toy haulers can have 4k-5k CCC .Another factor for us...there's no way we will reach GVWR. We camp in campgrounds...no boondocking, so we never fill our tanks at all and dump onsite. At best, with our Vespas, we're in the 1500# range for cargo in the unit.
Looking at the 328M says it has a 16500 gvwr and a 12400 dry weight (UVH)= a 4100 lb CCC (cargo carrying capacity).
When choosing a trailer always look at dry weight and gvwr. You know you won't tow the trailer at its dry weight and "only you" will know how much you will load in the trailer.
This 16.5 gvwr trailer is a typical problem deciding on a srw or drw as its pin weight plus a hitch and other gear in the bed is just out of reach of the F350 srw rawr truck.......however if you load the trailer to 14k-14.5k or so then the F350 srw has enough axle capacity to carry the load.
We don't know how many toys or how much weight you add to your trailer so some folks use 20% of its 16.5 gvwr.
If your going to carry more weight than the trucks tires/wheels or rear suspension can carry many folks go with 19.5" tires and wheels with some type of after market rear suspension help.
Your choice their.....just be aware "legal" overweight issues.