They are technically different springs. But you can mimic the roadster spring. Here's what I would do ---- number the leaves from 1-10 starting at shortest. Leave out 2,4,6. The ride will soften and it will lower the back a hair ---- by the combined with of three springs. Maybe a bit more because the 7 leaves left will most likely compress a bit more. Search for Jim Brierley's advice on the same subject.
You want to save the leaves because you may have to use them together on the bottom of the 7 leaf spring pack that you've just created. The U bolts that bolt the spring pack together may not tighten up on your 7 leaves ---- you may need that thickness to get those bolts to tighten. Putting them back on the bottom serves that purpose.
Any issues that may result are your issues ---- not mine; keep reading advice before you make this change to assure yourself that I give you competent advice. This is your liability.