The RP-8000 has lots of room inside so space is of little concern. The last RP-8000 crossovers I assembled used a board of around 4" x9" which was plenty of room. That board accommodated the tweeter and upper woofer circuits.
The lower woofer circuit uses only a single iron core inductor which is large and heavy and can be mounted separately on its own board, or even secured directly to the floor of the cabinet.
Once you receive the components and get them layed out on the table in front of you, in your desired layout, you will know exactly how much space you need. I see no benefit in cutting those out before having received your components and determined what layout you will use.
Regarding board material, I most frequently use 1/4" Baltic birch ply. Anything similar will work. I personally don't like to use mdf for crossover boards, but any other solid or plywood material, hardboard, should be fine.
Good luck with your project.
Elon
Ezeecrossovers@gmail.com
