[digidesigner]

You need PTHD3 as for 64 tracks you will use 2 connectors/ 2 cards and if you need to monitor thru an external IO box that must be then connected to the third card. Are you sure you need to monitor? I mean you have a d-show system that you can use right? You can mix down to assignables lets say 1 and 2 (PT output 49&50) and patch these back to any free input channels. Then you can listen to these channels if you need to monitor but pushing a solo on a input channel would be the same so I don't think there is that much of a point in "monitoring" anything. And if you are not running the show then you have no control over gains and stuff anyway... you would need to go and tap on the FOH engineers shoulder for each problem and he might be busy anyway... So as long as he/she is not pushing the gains and all the lines work you will be fine.

But yeah, AFAIK you can monitor thru an external box but I think you need to get word clock from FOH rack to your box for it all to work as D-Show will be the master clock device.

You can choose whatever Pro Tools version you like (from the ones that were available since Venue systems are out at least)