I use tin goat leather it is tough what are you using?

What method do you use for your tie on nock? Is it just a thick string with a constrictor knot?  I don't t have any serving string since I am not making my own bow strings

BCY Nock Point Tying Thread you can uses dental floss or strands off old strings will work.

The formula for determining spine at 28 inches was developed back in the day of all wood bows.  You have four additional features on your set up that require additional spine.  As noted, 160 grain points require about 5# more spine than 125 grain heads.  Add another 5# for high performance bows, another 5# for low stretch strings, and probably another 5# for the shelf cut to or past center.  Long story short, you need spines in the 60-65# range (and maybe even higher) for your set ups.

Ditto
I shoot a very similar setup 47@27.5 with a 29” 60/65 160gr point shoots lights out bare shaft tune out to 20 yards.

I always went with how much the arrow is above square with string regardless whether you nock above or below

I use two tied on nocks and shoot split , less wear on glove …

Oh they are smitten with the bows for sure! We all shoot together just about every day..and my 9yr old is set on going with me for Whitetails in a couple weeks, we just got her Zwicky Eskimo weighted with lead to match the 160gr field points she's been shooting all spring and summer...Even got some wool goodness coming from Theresa over at Asbell wool coming for us both! Can't wait to hit the woods! My 11yr old wants to go after little critters shooting off the knuckle and the 5 yr old loves sneaking around pretending the bales are a deer! So fun!