do you have the 45 degree angle bracket between the firewall and brake booster? I do but is also angles down like that. I corrected it a little with a washer on each of the 2 lower studs between the bracket and hydroboost.
I think the downward angle is intentional, If it was square to the firewall I am pretty sure it would hit the hood. On the leak, mine did too, seeping out of the top seal. I noticed when I bled the brakes it didn't suck the seals in the cap down as I used up the fluid in the reservoirs. I first thought it may have been a poorly stamped cap, but after not really being able to come up with a billet one, I took a closer look. cap "looks" ok, but the top edge of the master cylinder (which I bought new, not rebuilt) was not so great. I ran a fine flat file across the top sealing edge and problem became immediately visible. I took me about 20 minutes to file it down to where I thought it might seal. it was a pain in the ass to try and file it without getting metal dust in the master cylinder. there where high spots and low spots but also some parts filed easily while a couple spots were so hard you could hardly get the file to cut. also I slightly tightened the spring bail that holds the cap down.
All that being said, I am not completely sure I cured the problem because I just did it and have not really driven it much since then, But I think there is a good chance it is fixed.
I think my lesson is to check this before installation of the master cylinder next time.