Two concerns I would have are the weight and maybe the bumpiness. A harrow doesn't really create much resistance. I don't think your BX would have any trouble pulling a 6' harrow through the soil. I have a 6' harrow I use on a larger tractor that I think weighs about 500 lbs. We have sandy soil, but it's pretty rough going when smoothing it out after it's been plowed. I use an old 45 hp ford for the job. I wonder if you would do a lot of bottoming out on a BX.
It really depends on the conditions. If you're plowing soil that has established grass in it, you're going to end up with big clumps after plowing that I don't think a BX could handle driving through. If it doesn't have grass or thick weeds and it's sandy you might be able to get away with just harrowing and skip the plowing.
I use my BX 2350 to cultivate between the rows in a 2 acre garden and I came very close to buying a 4 foot harrow for the job. Instead I bought a cultivator with Danish tines. It has worked so well that I do not think I'll need to plow next year, just harrow, which a lot of ag people are in favor of because it doesn't dig up deeply buried weed and grass seeds.