Whether the Burton Seven is a good board to split or not depends on your expectations. For all I know it's a pretty soft board, isn't it? Most people tend to split pretty stiff boards. I have recently made my first DIY using my old soft Nitro and I'm extremely happy with it. Being an unexperienced splitter I didn't want to spend a lot of money and screw it up.
So my personal opinion: go for it!
Regarding the Burton inserts: Those are not a huge problem! Have a look at this German website:
Mr Wildschnee (he's also in this forum using the nickname "Burton") is a very experienced splitboard manufacturer and he has successfully split some Burton boards. Just have a look at the pictures and if you have any problems with translating the instructions feel free to ask me or him directly.
Bienvenu AJ to the fun of DIY split. Spend a lot of time getting your line and guide well set up and as mentioned, use a good blade. Take your time and watch a bunch of videos on youtube and read through the how-to's on this forum and if you are handy, you can do it.
I made mine 3 years ago now and it still rocks like a champ.
_________________ the mtl_ripper always hunting EC/BC