As someone that works primarily with guitar players rather than solo (and live bands more than duos), I find that the primary reason many guitarists (and other players sync-ing with some kind of automated backing) have such difficulty locking to the machines is inadequate monitoring of the drums.

If you think about it, in a live situation, there is never the slightest difficulty hearing the drummer! Not only is he typically louder than an arranger's drums, but he is physically located in a different area to the keyboards, horn players, bass players etc.. This makes it easy to hear him and 'lock' to his tempi. So making sure the guitarist can hear the drums front and center is very important, the more so the louder he plays.

But... typically, a drum track is mixed in with the keyboard parts, so he never gets this separation. And add to that, in all honesty, most arranger players I have heard, live or recorded, tend to place THEIR sounds somewhat louder than they would be if mixed by someone more detached from the playing..! Now feed THIS to the poor guitarist, and now most of what he hears is YOU, not the 'drummer'. So he may often struggle with being able to hear the drums well enough to lock to, especially if you are willing to concede that perhaps YOUR playing isn't exactly locked tight to the groove either.

Recording yourself live as a soloist, and being brutally critical of rhythm/lead balances and 'groove' is the first step to helping your poor guitarist out, and getting used to hearing YOUR parts buried in the mix (at the correct level) rather than loud and proud goes a long way. But if your arranger has separate outs that you can split the drum Parts off to, this is perhaps the ideal situation, as then the guitarist (and anyone else you play with) can now dial up the drums in their monitor without having your keyboard parts drown them out. If you don't have separate outs, but run your PA in mono, you can try panning the drums to one side and all keyboard parts to the other.

Bottom line is constant self-recording, both before you add the guitarist, and afterwards. Adjusting your keyboard part levels down to where they need to be (after all, with a guitarist, you are now HALF the rhythm section, not all of it!), and then getting used to hearing yourself less well than you perhaps currently do in the mix will quickly get things settled down and comfortable for you BOTH.

Really great advice Diki. Thanks!

I think you'll just need to try it out. I sometimes play with a guitar player/singer. Some songs seem to go better with just bass and drums while other songs various other parts will work out good. A few styles I use all the background parts and we like what we hear.

Wild Thing" by the Troggs

My advice? Don't. Unless somehow you get more than twice the money. It's more work for you. You have to make considerable changes in the way you do things. You have to split the tips. And the girls.
DonM

Don, everything you're saying is true! If I felt like I had the vocal, KB, and entertaiment skills to keep a crowd engaged several hours I wouldn't have to worry about finding other players to work with.