I found a solution. You can use seq, as long as "Scheduler in Overdrive" and "in Audio Interupt" is activated. After recording a sequence send a "hook 1.00534" message to seq to speed up the playback. It’s better to use hook and not the "start " message, because the latter is only an integer value and so your playback precision won’t be sufficiently tweekable to "sync" your midi to audio for longer track durations. Also, the hook parameter value may vary on your machine. I attached the patch that lets you record audio and midi simulatenously (I used Soundflower for that) and then play it back. With this setup I managed to fix sync up to about 10 mins of audio and MIDI. After that I got tired of tweeking hook, testing, tweeking hook, testing….