I don't know when DS7 hit 40 inches but he was able to ride the 40" rides at age 3. He hit 44" and rode Space Mountain at 4. He was finally tall enough for RNR on our trip this January. He was 6.5 and was so excited. At his seven year checkup in April he was 52".
DS4 was also able to ride the 40" rides at three and this spring barely made the 44" cut for EE. He got in line for Space Mountain as well but decided at the last minute not to ride.
One thing we found with DS4 is depending on the shoes he wore he sometimes made the height and sometimes not. When he was 3 the first day in MK he had sneakers on and had no problem with the height requirements. The day we went to Epcot he wore Tevas and just missed the height requirements for TT. We went back to the room and changed his shoes!!
DS4 was also able to ride the 40" rides at three and this spring barely made the 44" cut for EE. He got in line for Space Mountain as well but decided at the last minute not to ride.
One thing we found with DS4 is depending on the shoes he wore he sometimes made the height and sometimes not. When he was 3 the first day in MK he had sneakers on and had no problem with the height requirements. The day we went to Epcot he wore Tevas and just missed the height requirements for TT. We went back to the room and changed his shoes!!