Valve springs

Looking for some advice on spring set up. I intend to order some TF240's for a 448, I am using a XE282S and 1.6 rockers. The valve springs in the FT 240 head seem a little light (although comp said they would be fine) and the HR head seem a little heavy for a FT solid. I have seen the isky 8005A springs recommended for this cam more than once. My thoughts are to get the FT head and shim the springs up to 135lbs rather than use the head set up for HR cams.

Well, if Comp said they would be fine, who am I to say they are wrong? Especially when I like it on the light side.

I've shim many sets of Comp Cam valve springs to get between 145 to 175 lbs. on the seats as long as it doesn't exceed 375 lbs. open
I did one motor for 9secondphil that had a custom ground Comp Cams NASCAR grind that ended up with 435 lbs. opened with 160 lbs. on the seats, we remove the inner springs to break it in, which reduce right at 30 lbs. on the seats and close to 45 lbs. at max lift. He put a lot of hard miles on that engine on the street and at the tracks back east, spraying it as well as racing it N/A

The 8005a is a good match for that cam with 1.6 rockers.

OK, thanks, I think I will get the FT head and just shim the springs to match the 8005a springs. The inch rate of the 8005a's is 10lbs more and it has 135lbs @ 1.875 vs the TF springs of 120 @ 1.900 installed height. I would think the TF springs would be around 130lbs @ 1.875.
Can anyone tell me the inner and outer size of a shim that will work.