750mg is fine. It's a tad high for a 2nd cycle, but acceptable. I would just pin 1.5mL (375mg every 3.5 days) but your protocol is fine. If you stopped growing after week 8 then maybe only run the sust for 10 weeks. Your call... steroids are an individual thing.. you got to see how your own body reacts, and then gauge your cycles around that.
T-bol is a great oral. It's just really slow, and takes a pretty high dosage to get the desired results IMO. I find success w/ that compound when I run it for 8 weeks @ 80mg (sweet-spot). But 60mg should suffice for a first run w/ it. You can always bump dosage up if necessary.
If you've got some left over sust from your first cycle you could always use it at the beginning of your next cycle...
Sust (weeks 1 - 3) @ 125mg E3D
Prop (Weeks 1 - 7) @ 150mg EOD
NPP (weeks 1 - 6) @ 100mg EOD
^^ This cycle isn't 'ideal' for blood-levels, because the test dosage is a little wonky, but it's still alright. lol. I would probs run the prop for an extra week past the NPP just for good measure BTW
Regarding PCT timing... for sust it should begin 18 days after the last shot. This is because PCT should ideally start when all suppressive compounds have cleared the body. However, many people feel 14 days is enough for sust. It's your call, IMO it won't make much of a difference..