Tom,
you might consider getting a noise bridge and use the manual tuner 
alone.  All the experts go thumbs down on dualing tuners!!  in fact, 
easier yet, try reducing the R F gain to the transcweiver and set the 
tuner for max. noise and have a pair of eyes see if you are close to 
the magic 1 to 1.  If so, you probably don't need the bridge.  But as 
I recall the mFJ bridge isn't particularly expensive and would be a 
handy gadget to have around both shacks.
Other people have suggested you might try 20 meters the way things 
stand - and I would too agree with that.  Modern transmitting 
circuitry generally takes care of itself if SWR is excessive.  I have 
a bas SWR on 15, and whatever I try to do, my TS850 won't transmit 
there.  Survival of the fittest!!
Good luck.
Pat, K9JAUAt 02:16 PM 6/29/2015, you wrote:
>Dave:
>
>I understand, but here's my major question.
>
>Perhaps I should have just sent another e-mail with just this question:
>
>Don Terrell from Alpha Delta Engineering suggests that I simply use a
>wide-ranging tuner with my DXCC antenna out at the RV as it currently is,
>and call it good.
>
>So, here's what I'm thinking:
>
>I have an old MFJ 901B manual versatuner that is not being used for anything
>right now.
>
>Could I use that to basically tune the antenna, using receive noise as my
>indicator, and then just touch things up with the internal auto-tuner in the
>TS480?
>
>I have always heard that doing this would cause the tuners to work against
>each other, which could create real problems, but I never knew whether that
>was true or not.
>
>Of course, I do have an LDG TW1 talking SWR/watt meter at the home qth, but
>hate to tear things apart to use it during the relatively short times when
>we are camping.
>
>Does anyone have any wisdom on this latest idea?
>
>Tom Behler: KB8TYJ
>
>
>
>
>
>-----Original Message-----
>From: Dave Basden [mailto:[log in to unmask]]
>Sent: Monday, June 29, 2015 3:04 PM
>To: Tom Behler
>Subject: Your First Message Arrived
>
>Hi Tom,
>
>Perhaps the lack of comment was because everyone was recovering from Field
>Day, but your message did get through earlier.  As for using the antenna
>despite the high SWR, I would say that if the TS-480 will tune it then use
>it.  If the SWR is beyond its capacity, then perhaps an external tuner would
>give a match.  After that it's a matter of whether you can make contacts on
>20.  If so the SWR isn't something to worry about.
>
>73,
>
>Dave, W7OQ