Best Subwoofer Connection

 The only time I found it necessary to use my subwoofers high pass filter was when my main power amp was not powerful enough to drive the main speakers. 

 Considering the many variables when adding a subwoofer system I would suggest you try both methods of connectivity as well as placement. 

Since my Primaluna integrated amp only has 1 pre-out for a sub, I run my Lawrence Violin speakers at full range. My speaker dealer suggested I set the cross-over at 45hz on my E-110. Besides the cross-over setting, it's important to set the phase on the E-110 also. I was told to invert the positive and negative connections on the main speakers so they are out of phase with the sub. Play some heavy bass music and adjust the phase on the E-110 until there is a null in the bass. Then reconnect the speakers to the correct terminals. The bass on my system became tight without any bloat.
I suggest you experiment and decide which way sounds best!    

@rlb61
You should take advantage of the xover option with the E-110 giving you a true bi-amped system. The less expensive Dominion does not give that option. That’s why the E-110 cost more because of the high quality xover is included.
If I were going to buy a sub that would be the one for me.
Enjoy it!!

UPDATE: The e110 arrived today, and I've tried it both ways. Running the N804s full range with the sub filling in the bottom end is much more engaging amd satisfying to my ears. When I put the sub between the preamp and the amp, the sound became thin and lifeless. Perhaps that's because having one 10" sub to carry all of the lower bass makes little sense in a set up with full range speakers. I could see putting the sub between components when running monitors which don't go down below 60 Hz or if I had 2 e110s. By running the N804s full range, I get the benefit of four 6.5" woofers plus the e110. The sound is very full, although I think I need to get used to articulate bass instead of the boomy, flabby bass I've experienced with other subs. Different strokes for different
folks, I guess.

Well, there you go. Once I saw your current loudspeakers I figured that you would be going in that direction. Still, given the high-quality of the crossovers in the JL E110, you have plenty of options down the road.

And perhaps adding a second sub might change things, too. My plan is to go with two E110s or E112s simply because of something I read someplace about how stereo mastering is now done down to below 20Hz. 

For me, I wouldn't be done tweaking for another month or so. Finding the right location for the sub, pinpointing the crossover frequency, setting the phase and, finally, making tradeoffs on the sub volume setting so I didn't have to get up and change it when the album changed.

On the other hand, you're a vinyl guy so you're used to getting up. ;)

Great sub choice and nice system. (Jealous grin.) Enjoy!