Mackinnon's or lesser grey?

Yesterday I caught sight of a shrike of a sort that I'd not seen in Mbale before. It was obviously either a type of fiscal or closely related to these fellows. Having seen Mackinnon's fiscal in Kakamega forest (Kenya), I assumed this was one of those. Checking my field guide, however, revealed that it may more likely have been a lesser grey shrike. I did not have binoculars handy, so was not able to observe the features that would distinguish one from the other. Since Mackinnon's is a resident where it occurs and the lesser grey a migrant, and since I've not come across these in Mbale before, and since it is the height of the season for palearctic migrants to be passing through...my guess is that this was probably a lesser grey. Which would be nice to be able to confirm, as I've never seen that species before at all. Maybe I'll come across another one before the end of migration.