If you want to get surgical with tracks (work on specific bits and pieces) I suggest trying Realband.
It comes free with BiaB (Windows only, Mac version doesn't have it)
This gives you 48 tracks to play with; much more flexible. Generate 8 or 10 guitars and then cut/paste a final end result.

As far as Session Guitar goes, I don't own that one, so can't comment.
You would have a ton of other guitar options by either simply having someone play the guitar parts, or upgrading to Ultrapak with more Realtack options (more guitar players).
I don't work for PG, nor am I trying to 'upsell' you, just speaking from experience using these programs.

Simply put; the more Realtracks you have available the better your experience and end result.
And using RB, you can generate lots of tracks and figure out what parts you want to use from each .. without losing your previous work.

I do not work here, but the benefits are still awesome
Make your sound your own!