Re partition Linksys EA8500

The current device partitions are listed on the wiki page here.
I think that if possible, it will be quite beneficial to merge mtd15 and mtd17.
In that way, I can use all the space available.
Unfortunately, I do not have experience working with UBI.
My initial thoughts are:

  1. Boot from the first boot image.
  2. Back up the current flash layout.
  3. Remove/delete mtd17.
  4. Extend mtd15.
  5. Extend mtd16.
  6. Extend ubifs siting on top of mtd16.

Does it seem a valid path? Can anyone see a potential problem or can give me a better approach?
Thank you.