Is it possible to use Notion within Sonar if I upgrade to Notion 4 which I think is 64x and then use Rewire? Is here anyone else using both of this software together that can help a newbie like me?
Like Sidroe, I have Notion 4 x64 working with SONAR x64 via Rewire. It's pretty straightforward. There's no MIDI transfer between the two, so you can't drive SONAR instruments with your Notion score, but Notion can host VST instruments in addition to playing it's own built-in orchestral sounds, and sends the audio back to SONAR in sync with SONAR tracks when you start playback from anywhere in either app.
Ultimately, I think it's probably best to bring the MIDI from your score into SONAR to get full control of dynamics and controllers, and to be able to use any instrument you want, but if you want to do the initial composition in Notion, Rewire will be more convenient than constant exporting/importing.
In addition to the lack of MIDI I/O, the main disappointments I have in using Notion with SONAR are that it only supports 44.1kHz for Rewire, and the Now Time only syncs up when the transport is running. If you move around in one app or the other while composing, you have to manually keep their views in sync or start/stop playback momentarily to get them on the same measure.
Anyway, if you go ahead and upgrade to Notion 4 and get stuck on something, just post back here or PM me.