Hello,
In your case I would install another AS Java landscape, dedicated to the ADS usage.
Because this will probably be used in a production setup afterwards.
I had this requirement back then, and we decided to set up 2 Java systems dedicated to ADS.
The first one is used for any non-productive usage. ie all our non productive ECC servers are using this first ADS instance ( Sandbox / DEV / QAS / Validation ) .
The second one is used for production needs. Our ECC production instance is using it.
We could have used the Java stack and ADS from solution manager for example ( or any other Java stack ) but the problem here is sometimes, you may have to update the solman java stack for purely solman needs. Then this has an impact on the ADS and would require some non-regression tests related to ECC interactions with the ADS.
As we wanted to have dedicated maintenance strategies, we decided not to do that, even if from a purely technical standpoint, this could be done.
Several documents are available to help you configure the ADS like the "Adobe Document Services Configuration Guide".
A sizing document is available : Adobe_Forms_Sizing
And also this document :
ADS Landscape Recommendations.
I don't have the links to post them here right now but if you do some googling, you'll find them.
Hope this helps,
Best regards,
Steve.