In theory, this change will make 101.1's signal similar to 102.9's. 1 meter = 3.28 feet, so this means the two stations will probably be running separate antennas with 101.1's about 9.84 feet above 102.9's, unless I am reading something wrong. Also, 101.1 would be running only 200 watts less than 102.9. I assume there are no issues with this move on needing to protect co-channel class B WGIR-FM serving Manchester, NH.
Nope. 0.3m = ~1' (not 9.84'). Unless one or both of the stations is/are directional, it appears that they will be sharing an antenna. The slight difference in height might be due to rounding or differences in surveying.