In reply to Jackwd: Back to topic for a mo...
FYI: I have just done my first E4, Jetrunner, and popular soft E4; I have done about 4 E3s; about 8 E2s, but loads more than 16 E1s (talking on-sight here, mainly). At first I thought your strategy was doomed to failure as you might make silly assumptions about what you are capable of, but actually, perhaps it could work quite well, as without thinking about it, I did something similar.
I would say, however, that in my list of E1s, there are quite a few 5c routes, which I think has been important in getting into E2 and E3, and you are right to focus on bouldering too. However, on the positive side, Font 7a is well hard compared to the cruxes of E2, E3 and most E4 and getting solid at 7a is very different from having done a few and perhaps being solid at Font 6b+?, which I think would be a more useful (realistic) goal for your Trad aims. This is, at least, my experience.
But then, of course, I am me and you are you, so what do I know? But good luck,
Cake