Hey, OP. That's a nice telescope you have there. I'm not sure why your thread is so slow, there used to be a lot of astro shooters here.
If you're imaging with that scope without guiding, a barlow will only hinder you by extending your exposure times and exacerbating motion. It would be great for general observation though. A reducer will also not serve you very well because you'll only be using that for deep sky objects that require even longer exposure times... again, you'll want to be guiding. Given your setup, I'd go with the barlow because your exposure times for planets, the moon, etc will be much shorter than deep sky even with a reducer and you'll be able to get away with more. Plus visual observation will be way more fun. Even that cheap barlow you posted would be fine. It's just a simple 2x mag, don't worry about it. The main thing by far is not pushing the scope beyond its limits, which you wouldn't be doing.
Still keep an eye out for good deals on 1.25" eyepieces though because you don't have to use a barlow. Just use a more powerful eyepiece. Maybe check for 12mm which should be pretty decent on that setup. 1.25" will be handy down the road should you get another tube. They will also be easier to sell. Pic rel is what I use as well as E-Lux. All are excellent despite being made in China. I've used $1000+ eyepieces before and the differences are mostly toward the edges. You'll be fine. Chinese eyepieces are great as long as they are from one of the bigger names who actually have some form of QC. They require better tolerances than a 2x barlow. Also, remember that diagonals change your focal length and you don't have to use one at all. That adds a bit more flexibility.
Good luck bro, keep posting here please. Also
>>4156171 was me, let me know if you think there's any way I could send you something if I come across it. There's always old gear for sale where I am and shipping stuff that small is trivial.
