Trick Flow Heads: Conflicting Info on Mechanical Roller Spring Pressure

I could use some help making sense of necessary mechanical roller spring pressures, and therefore the parts, for my setup since I'm in the market for a set of Trick Flow heads for a circle track LA360 that will turn 7,500 RPM. The cam will have 0.640 lift after correcting for lash. The issue is that the information I'm getting from Trick Flow's advertisements and their lead parts tech over the phone isn't matching what two custom cam grinders told me, which is that I want at least 220# seat and 640# open for a 0.640" mech. roller cam.

Let me lay out the math for the two assembled head options Trick Flow recommended to me:

Trick Flow 61417802-C00
Advertised Cam: Mech. Roller
Advertised Max Lift: 0.680”
Installed: 1.90”
Diameter: 1.55”
Rate: 427#
Seat: 175#
Open at 0.640”: 448# (0.640 x 427 = 273 + 175 = 448#)
Even though the 61417802-C00 is advertised for 0.680" mech. roller, the springs will only give 175# seat (too low?) and 448# (way too low?) at 0.640" lift. Outside of shimming range.

Trick Flow 6141T784-C00
Advertised Cam: Mech. Roller
Advertised Max Lift: 0.700”
Installed: 2.00”
Diameter: 1.56”
Rate: 500#
Seat: 240#
Open at 0.640”: 560# (0.640 x 500 = 320 + 240 = 560#)
Even though the 6141T784-C00 is advertised for 0.700 mech roller, the springs will only give 240# seat (good) and 560# (too low?) at 0.640" lift. Outside of shimming range.

I also looked at 1.55" +- diameter springs for 1.90" and 2.00" installed height available on Summit, and these are the closest I found:

Comp 999 Springs
Installed 1.90”
Diameter: 1.55"
Rate: 633#
Seat: 196”
Open at 0.640”: 601# (0.640 x 633 = 405 + 196 = 601#)
These springs provide 196# seat (too low?) and 601# open at 0.640" (too low?).

PAC Racing PAC-1325 Springs
Installed: 2.00”
Diameter: 1.55"
Rate: 644#
Seat: 250#
Open at 0.640”: 662# (0.640 x 644 = 412 + 250 = 662#)

These springs seem like the correct ones at 250# seat (good) and 662# open at 0.640" (good).

I haven't explored all spring manufacturers to see what options are out there for around 1.55" diameter at either 1.90" or 2.00" installed height so I don't have to pay for the pads to be machined and so I can use the valves and retainers that come with the Trick Flow heads, but it appears I would need to buy Trick Flow 6141T784-C00 heads and swap out the springs for the PAC Racing PAC-1325 or similar. This route still looks quite a bit cheaper than buying bare heads, loading them with valves/springs/retainers, and having my machinist dial them in.

I appreciate input on this situation and if I am correct that the Trick Flow 6141T784-C00 heads are not properly set up for a 0.640" mech. roller cam and that I would need to swap out the springs to get a minimum of 220# seat, 640# open. If you know of any 1.55" +- diameter, 1.90" - 2.00" installed springs other than the PAC-1325 that will do the trick, I'd appreciate knowing of them too.