Hi
We had a similar setup (development) but after a while we opt out and decided to use Action in page that generate summery on screen for review (on for sure report to print). These are what we have learned.
1) We used Factbox and the reason was it had less impact on performance and more room. But we tested fields in page but it was not ideal.
2) We used Custom Field and needed to keep the options minimum. Since in the page or in the factbox we needed to define them to show sub-total. Anytime we need to add a new "value" to custom field it was a development to add that value to factbox for total purposes. Hence, we need to deal with lots of limitation.
3) It impacted BC performance (SaaS) because of all calculation.
The short answer is yes it is possible but need some pre-evaluation.
