DIY monitor advice sought - have cabinets

I bought a set of monitor cabinets off an auction site a few years ago thinking I would try my hand at DIY speaker building at some point. The cabinets were from Platinum Audio. I think the ones I have are for the Studio 1 model, so pretty identical size to the Solos. I am now thinking about making them into speakers, but I know NOTHING about this stuff. I cannot follow a crossover diagram, I have never done any of this wiring. I know that there are kits available out there and I have been researching these. Thing is, I would like drivers to match the cutouts in the cabinet, and I am thinking of going with a ready-to-go kit due to my inexperience.

The cabinets are 12 ¼”x8”x12 1/4 ” (hwd), with a 1” front baffle. It is a tweeter, midrange/woofer setup, two driver holes. They are recessed from the baffle, with these recessed areas being 4” and 6.” I do not have the back panel of the speakers, so I would need to make one. There is some material there, but in the original design apparently there was a plate with the speaker terminals, ports, and heat sink in the middle of the back side of the speaker, so I just need to replace this area.

Also, my web research suggests that the original speakers had a 1” tweeter and a 5” mid/woofer. Most important to me is that I get a kit that I can assemble into these cabinets, and get the proper fit for the drivers. (I would like to have a perfect fit into these recessed holes so as to have a clean, flush-mount look without having to cut new holes.)

I would appreciate any help that can be offered. I am not looking to spend more then a few hundred dollars on this, and I already have ACI Opals in my main system. These would be to have fun with and possibly replace the Opals.

I am familiar with some of the web forums and some of the factory direct manufacturers like gr research, selah audio, adire audio, zalytron, madisound.

I am seeking advice on how to proceed and what kits to investigate. Also, I have been wondering about the value available here. These speakers will be about the same size (although heavier) than Triangle Titus, but those are available used for around $350. Am I going to beat those? I like the idea of building my own and using these cabinets, but if it doesn’t get me beyond what can be had for about the same price used, I might just try to sell the cabinets, as they are quite nice.

Room size: approx. 22’x14’x7’ ceilings, opening to kitchen.
System – digital, JVC changer or Pioneer PD-65 through Audio Alchemy jitter reducer and DAC
Anthem Integrated 2, ACI Opal mains, Paradigm CC-370 center, Sherwood Receiver for HT.
Music – Chris Whitley, Lyle Lovett, John Hiatt, Allison Krauss, Coldplay, U2, etc.