Hey Goo!
Yes, I kind of modified the Jacks regimen a bit. I know they say to use Finish for the last two weeks. I took a stepped approach increasing the amount until it was the 100% Finish product for the last 2+ weeks.
So for Autos I counted on 11 weeks total time. I mix 4 gallons at a time so the math was easy. Regular formula into 4 gallons. Then regular formula for 3 parts and Finish for 1 part, etc...
Until Flowering starts I was running 80% strength.
Grams per gallon : Part A: 3g , Epsom salt 1.1g , Part B 2g
Totals :12g A : 4.4g EP : 8g B
Full strength Finish at 100% is 5.42g Finish and 1.1g Epsom
80% = 4.34g Finish and 0.88g Epsom (I just make it 4.4g and 1g/gal)
Up to flowering transition: 80% strength Jacks. I'm currently doing a run with 60% as the 80 was a bit N heavy.
Once flowering kicks in around week 5 I add 25% "Finish" into the blend.
So out of 4 gallons it's 3 parts of the 80% formula and 1 part of the 80% strength "Finish"
25% Finish blend: Part A 9g : Epsom 4.3g : 4.4g Finish : 6g Part B
I mix in that order with Part B last.
Into 4 gallons of water
Weeks 5/6: 25% : 9g A : 4.3g Epsom : 4.4g Finish : 6g B
Weeks 6/7 : 50% : 6g A : 4g Epsom : 8.7g Finish : 4g B
Weeks 8/9 : 75% : 3g A : 3.8g Epsom : 13g Finish : 2g B
Weeks 10/11: 80% Finish : 17.4g Finish : 3.5g Epsom
Anything past week 11 I just continued the Finish/Epsom blend. I use RO water and I add a silica supplement as a pH buffer. That's it!