amber & brown split batch - comments?

The base for a brown and an amber ale that I was thinking of doing were pretty close, so I'm just going to mash the base and cap each to make two brews instead of just the one. Let me know if you have any suggestions on either recipe

Amber
OG: 1.056ish, IBUs: 34ish, 5gal
7.5lbs Marris Otter
1.5lbs Munich 10
0.75lb Crystal 40
0.5lb Crystal 80
0.25lb Biscuit
2oz Pale chocolate
0.5oz Summit @30
0.75oz Summit @15
0.75oz Summit @5
1oz summit @0
1oz summit @dry hop
Wyeast 1882 - Thames Valley II

Brown
OG: 1.056ish, IBUs: 40ish, 5gal
7.5lb Marris Otter
1.5lb Munich 10
0.5lb Crystal 120
0.5lb Crystal 60
0.5lb Chocolate
0.75oz Nugget @60
0.75oz Nugget @15
0.5oz Wet Nugget cones @0
undecided, maybe Wyeast 1768 - English ESB

5 gal each or take a 5 gal and split into 2 2.5's and then add the crystal etc to each seperately?

This seems like it woudl be doable and give you 2 brews for the time of 1 mash - although getting both going and keeping going would be anoying. You could also 'keep' the mashed wort for a time since it will be boiled - If I were to do that, I'd bring it to a boil for a few minutes covered and then use it by the end of the next day - unless you want a sour beer.

Your recipes look fine... Just a thought, is that once they are done, you could do a 50-50 blend with part of each for a pseudo Nut Brown Ale... albeit a little hoppier. Then you would have 3 beers.

ok, im finally getting around to doing this one this weekend. i've tweaked the recipes a bit, any thoughts? I want both to be fairly malty, but with the amber having a noticeable hoppiness

American Amber:
5gal, 1.056 OG, 31 IBUs, 14 SRM
7lbs Marris Otter
1.5lbs Munich II
0.75lb C80
0.75lb C40
1oz Pale Chocolate
1oz Cascade @FWH
0.75oz Cascade @15
0.75oz Cascade @5
0.5oz Cascade @ Dry hop
WLP002

American Brown:
5gal, 1.055 OG, 34 IBUs, 25 SRM
7lbs Marris Otter
1.5lbs Munich II
0.75lb C60
0.5lb Chocolate
0.25lb C120
0.75oz Nugget @60
0.75oz Nugget @10
Pacman yeast

Mash the MO & Munich @153F, steep the rest for their respective brew. Ferment @66F