Coming in late to the party here. Too bad that because really....your off to an excessive start as far as amplification, and the Tactiles chosen are really anemic in performance, and are being slated to receive about 5x the power needed to blow them up.
Of course your own use and expectations will govern just how good or bad things get.
I've been using Tactile Transducers for Bass Supplementation since 1978-79
All things "Transducer"...tactile or otherwise, have been my focus for almost 40 years now. I've interacted with every Mfg from Aura
to Solid Drive
to , anything worthy of note from PE
.....so on and so on. Some have called on me for design advice...others simply taken older concepts and cloned them as best they could. Doesn't matter....I know what really works and what types / brands are either worthy or outright shams you should run screaming the other direction from.
I don't know what at this juncture I can do / add, except advise you on what the truly correct way to match up impedance would be, install the chosen "Shakers" most effectively (Chairs...Floor....Platform? ) or...."shake it all up" and send you down a "best possible path"....and still do it for the least amount of money possible.
Amp choice is paramount....and what you've chosen is not ideally suited but any means.
Wiring done with the right Amp choice can be as simple as providing a 4 unit - 2 Ohm Parallel'd Load to a Amp costing almost 1/2 the amount you've spent, and providing +3x the stated power of your current choice.
When it comes to effectively producing Tactile Effects, the availability of really ample amounts of "CLEAN" power, achieving "CORRECTLY" produced LFE frequencies, and doing it all using Tactiles that are not essentially "junk" is all of utmost importance. Fudge on any aspect of the equation and there is no way to overcome the poorer results.
I do have a lot of other things I'm involved in that take a capricious amount of my time, but I saw your post when I came on to overview AVS Members' comments about the Outlaw Ultra X13 Sub
and felt compelled to intercede.
If you want more input from my direction, just post or PM at your preference. My time is yourTime as much as I can make such possible. Questions that require time sensitive responses should be emailed or PM'd, and the responses then posted.
And remember...there is a real difference between accurately conveyed LFE "Tactile Resonance
", and inaccurate Bass "thump and bump...shake and rattle".
Tactile "LFE" should not be a acronym for receiving a "Low Freq. Enema".