The draft regulations only specify the minimum length and width of an enclosure. So for a Coastal you could have a 90cm long x 60cm wide x 5cm high enclosure. Impractical but within law.
The regs do not state a minimum length and width of a snake enclosure. Appendix B provides some examples of compliant enclosure sizes and calculations but they are not 'set' dimensions that you must follow - You can follow them but these are only examples of sizes that comply - You can build any shape or size that complies with the requirement of Section 4.3
There was discussion about this in earlier threads ...... as long as you meet your minimum floor (and/or wall for arboreal) area for your Class, and the smallest floor dimension is no less that 20% of the length of the snake enclosed within, it complies. The enclosure can be any size or shape as long as it complies with these 2 relatively simple measurements.
I have enclosures that are all very different in size and shape, but all comply (in fact greatly exceed) the Cops.
Thomasss.....To answer your first question - What is the biggest snake you can keep in your proposed enclosure? The minimum floor dimension is 600mm. This dimension can be no less than 20% of the largest snakes length so 600mm x 5 = 3000 (3m). This applies to all classes of snake that you may wish to house in that enclosure.
Your enclosure 'area' for the purpose of Clause 4.3.1.4 is 1600 x 600 (for terrestrial species) or 1600 x 800 for arboreal species. Both your Jungle and Coastal are arboreal so the latter is your area to use. 1600x800 = 1.28mSq.
Min area for Class C (Jungle) is 0.4mSq so technically yours is two thirds 'bigger' than the min required by the COP for a Jungle, and can house a Jungle up to 3 metres in length.
Min area for Class D (Coastal) is 0.625 so technically your proposed enclosure is almost 'double' the minimum required by the COP and can house a Coastal up to 3 metres in length.
Your enclosure actually 'just' meets Class E (1.225mSq) and will legally house an Olive or Scrub python as long as they did not exceed 3 metres.
I have heard on good authority that 'minimum' requirements will be reviewed after 12 months and increased - so expect changes in 18 months or so (these new COPS are not mandatory until next year). I personally don't mind the snake regs....In most cases a 'minimum' size by the regs would are smaller than I would want to keep a snake in under normal circumstances anyway.
Hope that helps....