Hi,
I've got a couple of FEs and have run at least one since 2003, so I've been through a few sets of harnesses of different brands. The only ones I will buy now are the Schroth Formula harnesses. You mentioned you don't like the sub straps that go through loops (but I really don't understand why...) - these are designed that way as with essentially every harness designed for formula car applications, since the anchor points in formula cars are usually far aft of that in tin-tops, etc. To answer one of your questions, the sub straps in an FE are typically anchored to the points a few inches forward of the laps belt anchor points.
Here's a link to the HMS Motorsports page with the Schroth harness:
https://www.hmsmotorsport.com/products/Formula
Definitely order the pull up design. Far easier to get belted in whether on your own or with help. Very handy if anyone else (like a skinnier coach!) drives your car. And the Schroth are the only belts that have an adjustable section outboard of the pull up adjuster, which allows them to work with a proper foam or bead seat. I have not been able to find any other harnesses that will work - OMP, Sparco, Sabelt all have about a 2-inch long fixed section outboard of the adjuster, and the adjuster ends up buried in the seat pass-through and completely useless.
They are on the pricey end ($455), but worth every penny IMO. I have 3 sets on the way this week to get all the FEs in my shop through annual tech. If you go with them, call Billy at HMS in Mooresville, NC. Their container with a dozen sets just cleared Customs on Monday, but he said they were going fast!
These are 2-inch shoulder and lap belts for use with HNR. And on the shoulder harness mounting, they DEFINITELY need to be closer together. Per the HANS website, the anchor points for the shoulder harnesses should be 3-4" apart. Steve Stadel of One Formula Racing (Enterprises CSR and he's on Apex as sstadel I believe) makes a nice mount that attaches to those OEM points you are using now, and allows you to anchor belts closer together. I have those in my cars too.
Finally, now that I think it through, I am removing one set of Schroth harnesses (only difference is the 2" shoulder harnesses turn to 3" below the HANS for some silly reason) that are good through 2019. They are a nice dirty red color
If you would like to try them, PM me with an address and I'll ship them to you gratis.
Best regards,
Eric