Would adding the millisecond or H:M:S.F ruler to the timeline help? Using a different ruler and Aim Assist, you should be able to get very accurate time based placement of clips.

I completely get what you're doing, Bob, and have done similar projects a few times in the past.   I was going to suggest that the guitarist create broadcast waves so that you can import them at the correct location regardless of MBT, but the last two replies seem to be headed in a better (and more flexible) direction.
 
BTW, that's a very nice selection of tunes.  
 

Thanks Robert glad to help. You certainly help a lot. I know it sounds it a bit old fashioned transcribing stuff and writing charts. I am a bit old school. It is just that whenever I do it for a production it is always easier. Everyone knows what to play and where. I have certainly done jobs when I did not chart them out and they usually take longer. But even if it is yourself overdubbing the chart still helps and makes it easier. I put the corresponding DAW bar numbers on the chart too that makes a difference. After a while too you learn the chart and you don't have to sight read it anymore. Then you can free yourself and start playing the music properly almost. I have got a strong Jazz background chart wise, they spent years teaching us how to write good charts then they told us to learn the music and throw the charts away!
 
It is cool and fun and very rewarding usually to transcribe someone else's music. You learn a lot about good writing and arrangements. It also keeps your brain alive a bit.
 
Many original audio tracks are done to a click and will stay in sync the whole way through to your DAW session. But even with tracks that were recorded totally live without a click what I do is sometimes is cut up the original audio track to fit the midi track I am building. Studio One makes it very easy to shrink or expand audio regions to time stretch sections of the audio to fit the metronome of your DAW session instead. The original audio gets hacked up a bit but the good news is that anytime you unmute it in your session, you are hearing it in sync with your music. Handy to check anything you are unsure of.
 
What I wanted to say in my previous post too was that midi track that I start with eg a click, bass and piano basic chords can be expanded out to include simple clean drum grooves etc. I often use a General Midi synth to build that simple starting track. The old standard drums, bass and piano trio as your starting point. It can be used to represent any music or style and progression so easily. Once you have created audio for that guide track you can send it to anyone as well. I could play over your tracks so easily. I will play drums for you for example over your present project. In that case I would give you back all the drums in multitrack form. Many tracks all the same length and the whole length of the arrangement. The only thing for you to remember is that if you do cut any of my drum parts you have to work with all the tracks at the same time to preserve timing and phase etc..
 
I am doing a fair bit of this right now. It is wonderful to be able to work with very fine session players and I am lucky to be doing a lot of that at the moment. All these incredible live tracks get built up and you have so much to work with around the mixing phase. Having the chart means I can capture many passes quickly and they are usually all correct. No time is spent figuring out what is going on in the music, you have that nailed already. All the time is spent instead creating layers and takes etc..

Hi Robert, I too am going to take a stab at this but I might echo what beester suggested.  Create a new project and set it up according to your desired tempo (108) and the time signature per a specific section in your arrangement (project 2).  Import the respective guitar clip (project 1) into the new project.  Now change that imported clip into a groove clip and adjust its length in the Clip properties to match that of your project (2).  After that, bounce the clip.  You should be able to simply drag the bounced clip into your project 2.  Just repeat for each time signature change and guitar clip respectively.
 
My other suggestion is, since you already have the bed of the track laid out, have your guitarist rerecord the lead over your new track.  It just sounds to me that you two were working on two separate project instead of working on a single project and now you are trying to merge the two.
 
That's all I got for now.  I do a little tinkering around and see if I can find another method or perhaps a real solution and get back to you.
 
Kind regards,
 
Living Room Rocker

robert_e_bone 
BUT, because in my project I have all of these time signature changes inserted, my measures do not line up with his any longer...

 
Are you saying that if it wasn't for the time signature changes you would be snapping each clip to the beginning of a measure?  If so, then now you need to snap to a quarter or maybe eighth note (i.e. to a beat or half-beat).

Changing the ruler display format to SMPTE allows me the placement I need for the clips.
 
I just change back and forth between pasting clips and setting time signatures and such.
 
I believe the above will work fine.  Thanks to ALL for your assistance, 
 
Bob Bone