Old hat...

You asked so here's what I run
I have an ancient factory 318D . I limited the mechanical to 19/20*, and set the idle timing to 14*, for a total of 32/34 which is all the aluminum heads want. She's a streeter so I can't tell she's any slower at 32 than 36 so I just set it up the middle, and she makes plenty enough power to get into trouble with. So now because the 14* is in there to achieve the proper transfer slot exposure at 750rpm idle, I gotta run a two-stage rate-of-advance curve, So I reused the long-loop 318 spring which has about 4 degrees in it but won't be all in until 3400rpm. Then I dinked around with primary springs until I found one that barely keeps the idle timing at 14*@1000rpm and shes done by 2800.So
So now; my timing is 14* below 1000, then ramps up to 28* by 2800, then slows down to be all in of 34*@3400. So I mapped that out on a graph and went for a spin to see where I might find detonation, and finally found none. That is how I run 87E10 @185psi with aluminum heads. At 185psi the engine has gobs and gobs of torque at nearly any timing down there, so I quit looking for more.
After I got all that done, I started playing with Vcans, and found that my 230 cam/al heads liked lots and lots of cruise timing. I have an overdrive so she cruises at 65=2240rpm and the mechancal timing was like .78*/100rpm so 2240 was only about 24*. And you can imagine the crappy fuel mileage at that timing. So I went straight to the biggest in my collection which was 20*. So now I had 44 cruise timing. I went for a cruise. Every few miles I'd dial in some more timing with my box. Soon I was deep into the 50s and the running vacuum was still increasing at a steady-state mph. It plateaued at between 56 and 60*, so I decided 56* was good enough. So back at the shop, I modded that Vcan but could only get 24* out of her for a total cruise timing of 48*. Then I recentered my Dial-back to add the 8* difference.
So now when I hit the hiway, I just crank the Dial-back to where the Total all-source cruise-timing is 56* , and sit back and enjoy the ride. Sometimes on long drives, on what appears to be a level hiway, I still experiment a bit, but my vacuum gauge can't find much difference, and neither can the gas-pump.
If you recall, I just told you my all-in mechanical timing is 24* at 2240 rpm and 28* at 2800rpm. Most guys will tell you that is lazy timing. But the thing is my first gear TM (Torque Multiplication) is 3.55x3.09= 10.97 so this with the tons of torque that 185psi makes, is plenty enough torque to break the tires loose, and the then the engine spools right past the soft-timing zone. And any time I am in it, like in second or third gear, I don't care cuz I'm just tooling around. My opinion is you just can't run an automatic loose-convertor timing-curve, with a manual trans, and I don't even try anymore.
As to TM , in first gear you may be running 4.56x2.66=12.13, about 10.6% more than I am, so you should not have any problems with "lazy timing".
My second gear TM is 1.92x3.55=6.82, and my engine will break traction anywhere up to 50mph and more with 295/50-15s. Your second gear TM will be 4.56X1.92=8.76 which is 28.4% higher than mine. In fact your third gear TM is 6.38,nearly the same as my second gear! So I don't see lazy timing being a problem for you...... cuz it ain't a problem for me.
Bottom line then is; just limit the power-timing, and slow it down.
Then stabilize the cooling system temp to zero variance or as close to it as you can, and bring the heat up. You can't run razor's edge timing until the coolant temp is stable. If the electric fan is cycling, this is not stable. If the flex-fan cannot keep up, this is not stable. If the stat can't regulate to a single temp within a few degrees when the 7-blader cuts in, this is not stable. If the carb is sucking HOT!! underhood air that is constantly varying, this is not stable. So until you get the temp stabilized, play it safe with lazy timing and limit the power-timing to well below optimum.