You mentioned a 40 long by 30 deep bench.
I believe those dimensions would be ok except for the height. The 28 inch bench would be a deal breaker for me, too short and would really limit storage underneath.
I would likely opt for the garage since as others have said, once you start storing brass, scales or some day add another press you may need more bench space.
You could always throw a "cover" over the press, most folks won't know what it is even uncovered but the cover would provide additional opsec. Also, the cover is nice to keep dust and such off when not in use.
You could build doors for the lower shelfs or temporarily hang cloth/curtain the shelfs.
Also, as others have said shelfs are handy.
I thought my 8 foot by 22 inch bench would work with one shelf. However, I quickly found the need for another shelf and will likely add a set of shelfs behind the presses.