Sailtube length?

Cross posting on the 14 forum: I've arranged to buy a piece of 12" wide pipe that is 20' long. We need to cut it to get it home on our truck and am trying to figure out how long to make each cut. The shorter we cut each piece the easier it will be to get it home (30 miles or so on a mix of freeway and bumpy roads). We have a Getaway and a H14 so we could use some for each. Our boats are both in storage in different parts of the city and I probably won't get the chance to go measure anything. I have the battens for the HG mainsail and it looks like the longest one is less than 8'. I'm wondering if it is worth cutting two smaller than 10' tubes and using the extra one for ...?? rudders ?? extra other stuff?

Does anyone know what the minimum lengths I can cut are that are still practical for use?

Thank you for your help!

I made a tube for my getaway that is 8' long +/- an inch.
The sail in the bag just fits length wise.

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2004 Getaway with wings

thank you!