Hi and thank you for your question.
From the description you provided of the symptoms, I would suggest double checking your vent hoses to make sure they did not accidentally get kinked causing a restriction, If the hoses themselves seem to be fine and undamaged, I would suggest blowing back through them to make sure the internal piping in the tank for the vent system is not restricted somehow.
BTW, did you buy a new or a used tank?
Another test I would suggest is a fuel pressure test. Here you need a fuel pressure tester connected in line in the fuel supply line for the injectors. Start the biek and observe the pressure reading. Then. slowly increase the RPM as you observe teh fuel pressure readings. See if there is ever a drop in pressure. Off the top of my head I believe that system is supposed to run 40-45 psi fuel pressure.
I would imagine you inspected the inside of the new tank to make sure it didn't have any rust or debris in the bottom of it, prior to assembly and installation on your bike. If it was a clean tank on the inside, it should rule out any possibility of the filter being clogged or restricted.
If the speeds are low enough where you can achieve them in a parking lot with lots of room around so you would never need to make a panic stop, you could also test tank venting by opening the cap and seeing if the problem goes away. So, under those conditions, ride ti with the cap closed completely and verify the problem exists. Then, open the cap and ride the bike exactly like you just did when you were able to make the problem show up before, and see if you still have the problem.
If you don't make any headway with any of that, I would suggest putting the old tank back on and see if you still have the problem. If you do, you know it has nothing to do with the tank and we can proceed in another direction.