[new build] disk split plus disk compatibility question

[socra]

Searched the forum a bunch but can't seem to find what I need..

Currently have a windows server running flexraid 🤐with 5, 2 TB drives (several Seagates bought over various periods) holding my movie collection). Want to rebuild this server into an XPEnology box.

System is a Node 804 case with Mobo MSI H97M, an Intel Core i3 4160, 8GB RAM plus an IBM M1015 Raid adapter flashed to LSI IT firmware.
Also have an HP NC360T dual nic laying around (no sure whether to install that or not).

My migration strategy currently is: buy an 8TB drive, copy all the data off the 2 TB drives and rebuild the 5 drives into an SHR set. copy the data back and add the 8TB drive as a loose backup volume for some backups from my lan (photos, system backups etc) . I don't think adding the 8TB to the SHR set would make much sense since I would loose 6TB.
Would rather have an SHR2 but I need the total of 8 TB space to hold the data.

Question 1): should I split the drives between the onboard sata ports and the LSI card or should I place all the drives on the LSI card? (assuming that the onboard sata ports are detected and work with xpenology) Might be trivial to experienced builders but I consider myself an XPEnology novice

Question 2): I know synology has a very elaborate disk compatibility list. Is that list driven by the synology hardware or the DSM software? (In other words: do people using xpenology adhere strict to the list and should I keep in mind which type of xs version I use? ) (planning on using the 'good old 3615xs)
 

Remark: any comment or tips on a better migration strategy are welcome.
 

Thanks for reading!

Edited October 5, 2018 by socra