Ok, so we know we're talking the same language here, no pun intended Mate.
Just so you know ahead of time, the tapered panel Deist's are probably going to spin. That shouldn't be a big deal to you on a rundown from 200 to 250 ish, on a 3 to 400 car they will close up without a spinner mount.
You have two low speed options in a 14 & an 18, my suggestion would be to start with the 14 & see how "you" like it. If you want more hit, go up to the 18.
With an 18' tow line & 15' shroud lines you have 33' to the canopy, that'll work. Now your high speed tow line needs to be longer than that to prevent tangle.
The high speed you have sounds like an odd little critter, 30" to single shroud lines with a 12" center panel.
When you deploy a low speed on top of a high speed, the low speed will kill the air to the high speed & it will stop flying. It tends to beat the $hit out of the high speed getting dragged on the salt so if you don't need to use both, don't. You're only required to have more than one chute beyond 300 & even then you can run it down on one unless you need to get it stopped in a hurry.
Hope this all helps.
Sid.
