A Williams aperature sight on your 30-30 would be excellent. For hunting you want a large opening in the aperature. It is common to take the disc out and just look through the threaded hole. This is a geat hunting sight.
If you are new to peep sights, it may appear the hole is so large that you wouldn't be able to hit anything. This is not corect, your eye will automatically center the hole. Thus, in shooting, you just put the front bead where you want to hit and let fly. Do not even think about the back sight, as your eye will automatically center it for you.
If the threaded hole still appears too large for you, then drill a larger hole in the disc. The hole must be large enough to give you a good field of vision.
The Williams sight that fits Marlins, as well as Winchester 94s, used to be called the Foolproof. Not sure if they still call it that or not.
Now, the 30-30 for moose. This depends on where you hunt. If it is in the bush, where 100 yards is a longer shot, the 30-30 is all you need. Just take your time and get a shot into the lung area. Use the soft nose 170 grain bullets.
A 30-30 with the same bullets is deadly on bear.