What to pitch on top of Cali Common

Just brewed a Cali Common (Anchor Steam Clone I believe) on 1/3/12 and was already thinking of pitching another beer on top of it. Here's the recipe calculated at 38 IBU's off Beer Tools:

9.11 lb (85.1%) American 2-row
1.59 lb (14.9%) Crystal 60; Crisp
0.9 oz (33.3%) Northern Brewer (8.9%) - added during boil, boiled 60 min
0.45 oz (16.7%) Northern Brewer (8.9%) - added during boil, boiled 15 min
0.45 oz (16.7%) Northern Brewer (8.9%) - added during boil, boiled 5 min
0.9 oz (33.3%) Northern Brewer (8.9%) - added during boil, boiled 0.0 min
1.0 ea White Labs WLP810 San Fransisco Lager

What is a good beer to pitch on top? I was thinking maybe this Darker Higher ABV/IBU Cali Common

10.45 lb (78.4%) American 2-row
1.25 lb (9.4%) Munich Malt; Durst
1.0 lb (7.5%) Crystal 40; Great Western
0.5 lb (3.8%) Victory® Malt; Briess
0.13 lb (0.9%) Pale Chocolate; Crisp
0.72 oz (21.1%) Northern Brewer (8.9%) - added during boil, boiled 60 min
1.35 oz (39.5%) Northern Brewer (8.9%) - added during boil, boiled 15 min
1.35 oz (39.5%) Northern Brewer (8.9%) - added during boil, boiled 1 min
1.0 ea White Labs WLP810 San Fransisco Lager

Another question I have is when to pitch the beer on top as I have never done this before?

Looks like a good recipe to pitch onto a yeast cake.

I used to rack a new beer onto yeast cakes as my primary method of reusing yeast. It does work well. Usually I racked my first beer into a secondary and then racked the new brew onto the yeast cake within minutes. Sometimes I got away with airlocking my carboy for a day before racking the new brew.

Now I use the yeast washing method shown in a sticky note in this forum's Yeast and Fermentation category so I'm not using quite so much yeast. I just pitch the large jar of washed yeast into my new batch after decanting some of the liquid. Sanitation is so much easier now with Starsan than the old days of flaming bottles and such.

Reusing yeast is a great way to more miles from your ingredients, and racking onto a yeast cake is a good start.

Happy brewing.

Yeah, that's probably a good idea. I've done it before, but read somewhere it needs to be used within a week? I am sure that is over doing it. I got a stir plate, so it's pretty easy to restart it again before my brew.