In reply to BusyLizzie:
I did it in 2017 and enjoyed it - I was able to get over there a few weeks earlier and recce it by bike ( a lovely cycle by the way ! ). It's not flat, but not too hilly, more undulating, and most of the "bigger undulations" are at the far end of the loch, ie between miles 10 and 15 from memory.
May be back this year, but too early to say, Planning on Speyside Way race at end of August, and then Glen Ogle 33 in early November, so this could fill the gap between them quite nicely ! Might do the half if I decide not to do the full