A very deep see-through fireplace (deeper than 30") presents a different type of challenge. It's like two fireplaces were built, but they
forgot to put a wall in between the two. In such deep fireplaces, I
recommend using two single sided gas log sets, back-to-back. There are
some distinct advantages to such an arrangement:
1) Positive ignition. Two sets provide two ignition points,
avoiding delayed ignition that can result from multiple burners across a
deep arrangement with only one point of ignition. 2) Better gas economy. Can operate one side alone, if you are only in one room for an extended period.
3) Better gas control. Depending on the size of the gas supply, you
may not have sufficient gas volume to power a single set that spans the
entire depth. Splitting the gas demand over two systems permits better
balancing of the flames between the two sides.
4) Taller log stack. See-through sets tend to be flatter.
Your
main issue is plumbing to connect the two sets to a single gas supply.
If you will be using a safety pilot control (one for each set), you
merely tee from the supply to the inlet of each control. If you will be
match lighting (natural gas only), you will also tee from the supply,
but will need to install one manual valve at each burner for gas flow
control to each burner.