Low freq high pass: 12db or 18db when cost is same

[Hybrid fourdoor]

I'm looking to pair a dipole fullrange driver with a ported subwoofer, so I want to take out the strain of the bass from the full range, and also minimize the dipole canceling out the bass. The sub will have its own amp with an adjustable 24db XO, so in looking at a high pass XO for the full range I ran into a fork.

A 12db Hi pass at 180Hz (5ohms) is

C1: 125uF
L1: 6.25mH

A 18db Hi pass at 170Hz (5 ohms) is

C1: 124uF
L1: 3.5mH
C2: 374uF

Now I already own 2x 50uF & 100uF nonpolar electrolytics and 2x 50uF Dayton Poly.

So the price comes out to

12dB Hi Pass

6.20mH (16awg Super Q 266-932) $14.83
80uF (electrolytic 125uF - 50uF Dayton 027-358) $1.80

so a total of about $34 for a pair

18dB Hi pass

68uF (124uF - 50uF nonpolar 027-356) $1.30
3.5mH (18awg Jantzen 255-278) $6.45
320uF (374uF - 50uF Dayton poly 027-372) $4.25

Total of about $26 a pair.

So assuming that I think the sound of capacitors is a moot point, and the price is similar would I be better going with the 3rd order? It would cut the bass out quicker and hopefully integrate better with the subwoofer. Phase issues might be a concern (3rd order mating with 4th order).

Thanks.