This reply may be too late for your build but a good reference for what you are asking is Squadron/Signals Gato-Class Submarines #28. On page 20 there is a three-view drawing of the Balao (I know, not the right class!) which is very close to what you would see of a Gato below the superstructure. The bottom view is an exploded side view which shows the interior of the boat. It gives you a very good idea of what can and cannot be seen through the limber holes.
Obviously, the most forward limber holes over the torpedo outer door shutters are see-through. If you are modeling the boat with the bow planes rigged out then what you see through the holes in the bow plane recess is mixed. The bow-plane rigging and tilting mechanism, the capstan drive, the anchor chain drive and storage are all in this area and will block the see-through view to one degree or another. Any limber holes aft of the bow planes are blocked by pressure hull unless additional row of limber holes were added.
The diagram has a dashed line running horizontally which shows the position of the tank tops relative to the pressure hull. This can be your guide for determining if other holes can be seen through. The diagram does not show all of the piping, etc below the deck that obstructs see-through viewing however.
BTW, the decking is a mix of slatted teak and perforated steel plate so light does penetrate to some extent, more so under the teak.
Qualified in Submarines 1965
"D..n the pressure, Six-Zero feet!"
"Most men would rather die than think, Most of them do!" - Bertrand Russell
"Boomers hide with Pride"