First off great choice in amp.
Here is the problem, the amp does 510@4, 860@2, 1410@1
That sub is a dual 4 rated at 750 so the 860 @ 2 ohms lines but... If you have the power there why not use it.
Now all the prices I'm getting are Canadian so I'm gonna say it's somewhere between $150-200 US?
What you should look at is something that is a Dual 2 ohm so the final load will be 1 ohm and you can get the most out of the amp
Something like this, it's just an example there are several really good subs in that price range
https://www.down4soundshop.com/hannibal-hss-3212-d2-12-subwoofer-1000w-rms/
Now as for the LOC
When you have an aftermarket HU the RCA signals have power ratings.
Average HU puts out 2 volts, good ones put out 4-5 volts and really good ones are above that.
Your standard cheap LOC will only put out 1 volt if your lucky.
There are a couple ways to get around this.
Use a DSP (digital sound processor) but thats expensive.
Add a line driver, just one more thing you have to wire in
Or, get a LOC with a built in line driver.
You can get a good one for fairly cheap
The Audio Control LC2i will handle up to 400 watts input and has 9.5 volt RCA a=outs on it and it's only about $100 US
I think Dayton Audio make a good one for about the same price
The DSP-408