The canopy tapers at the front. Its about 15 inches wide at the point where the IP crosses it. The bit in the middle sticks up into the canopy area. (that's why it always hits the floor when you lay the fuse upside down). The shape of the IP just fits the canopy with 1/2 inch to spare either side.
Of course, at the risk of getting into a "modification" you could change the canopy - Buly's is much wider and would allow for more height in the IP. I'd have thought that there's more than enough room for a glass cockpit if you do without all the steam gauges.