Sync Reaper to Ableton

I have sync setup using midi Yoke & its working but the Tempo of Live is fluctuating up & down. Its pretty noticeable, is there any way to sort this out. I'm using an M-Audio 2496,its even happening with the buffer size set as low as 64 & at 64 its snap crackle pop. I've also tried adjusting the Midi Clock Sync Delay of Yoke within Live but this doesn't help either. If I can't get this sorted then Syncing Reaper & Live isn't an option for me, so any help would be much appreciated :)

you could try rewire - but only if you dont need to use vsts in ableton. you can still use the ableton fx and instruments.

live (non-rewired) sync is horrid,