Ficus lyrata is native to West Africa and widely grown as a house plant. They are great indoor plants as they are long lived, tolerant of a wide range of conditions and not subject to too many pests due to the hard waxy leaves. This plant has no problems dealing with hard pruning cuts as you can see on the old growth on the central stem. From the picture below (Credit wikipedia) you can see that when grown as a specimen away from other plants and not pruned it ends to be wider than taller:
For pruning you can go by a few ideas:
- plants grow towards the light
- they are more likely to bud out of new growth
I am going to go out on a limb here and guess that you live where the ceilings are around eight feet tall (~2.5 m). So you have as much room to go up as to continue going out.
You could certainly cut the new growth back a foot from the tips with a sharp pruning tool. Watch out for the white sticky sap which is an identification key for the Ficus species.
Or you could do something different. Seeing as you want it to stay at this width and new growth will likely come from the stems growing out at the sides why not wire the growth in the direction you want it to grow? If you have or can get common PVC coated electrical wire used in houses it has sufficient stiffness that you wind around the branches and use it to direct the new growth up. Wind the wire around the more supple new growth and leave it on for a few months. The stem should be set and you can remove the wire for reuse.