It's a tough one to figure out. Looking back, I'm glad I went off of test yet would have gotten back on a low dose more quickly with my protocol. With the higher test dose and tren I'd imagine you have nothing going on right now and a bottomed out sperm count, which would be expected.
It all depends how fast you want this to happen. If it's ASAP I'd consider once your cycle is over to remove test for an 8 week time period or lower to a very small dose....50-70mgs/week. I posted a study in this thread that shows clomid may be effective with a test dose below 100mgs, but even more likely with a dose below 80mgs.
It sounds like you are not insanely urgent so I'd maybe start some HCG when you drop down to your 250mgs dose, even a small amount. Again, it all depends on your timeline. I'd have different thoughts on an ASAP timeline vs 8-12 months.