easy-fast-easy /finish drill -- Cns recover

Doing exercises like finish drill,or easy fast easy, is correct to use long rests between the reps.
But i for example,doing the 20m finish drill with a 30m build up, i feel too long the 10’R i saw on the Vancouver. Maybe i am wrong on the build up,not enough fast for building good speed next in the 20m.
For example doing the first 30m in 3.8-4.0" with a 3.4 guy,will be enough fast?