I have another set of TF heads in the shop now.
This set has the 1.550 flat tappet springs and steel retainers.

The spring pressures don't really coincide with the spec sheet that comes with the heads.
The spec sheet shows these heads to come with TFS -16094 springs, and that they have 138lbs at 1.950/430lbs at 1.250, with a 420lb/in rate.
The TF dual spring spec chart on line shows different specs than that, and are closer to what I observed.
TF claims these are PAC springs, and the specs are the same as a PAC 1294, so that's likely what they are.
The specs for that spring are 175lbs at 1.900/442 at 1.275, 428lbs/in.

I have 2 calibration springs for my tester, and according to both I am within 2lbs of those springs.

The springs that come on these heads start to have some coil to coil contact at about 1.300, so at heights shorter than that the rate starts to climb pretty quickly.
The coil bind height is listed at 1.190, and while some would get that low, several wouldn't and were solid at about 1.220-1.230.

My observed pressures at various heights for all 16 pieces are;

145-150 @ 1.980
160-165 @ 1.950
185-190 @ 1.900

390-395 @ 1.400
420-425 @ 1.350
455-465 @ 1.300
465-480 @ 1.275
480-500 @ 1.250

My suggestion for someone using this version head/spring...... Especially if you're planning on running a flat tappet cam and using most of the available lift from the spring is to verify the installed heights and pressures.

This set of heads had the installed heights between 1.945 and 1.960.