Baltic Porters & Ale Yeast

I'm planning to make a zywiec porter ("Beer Captured") clone soon. Don't have lager yeast but will be using ale yeast (Wyeast 1056) - recipe states this substitute will produce a good porter (albeit somewhat different from the original recipe).

Questions I have:
- Lager yeast recipe assumes approx 5 week fermentation - would use of Wyeast 1056 assume typical 2 week ale fermentation? Would there be a benefit to having a longer fermentation for the "ale" version of the recipe (>2 wks, >3wk)?

- Would you keep this fermentation at relatively low temp for ale yeast (perhaps closer to 65F)?

It will probably be shorter for your ale strain compared to the lager strain. If you want to try fermenting it at the lower end of the temp range, it will take a bit longer but will probably turn out a bit cleaner. I see no benefit of a longer fermentation like you suggest, short of ensuring the beer is done fermenting, other than allowing the beer to clear for a longer period of time.

None of commercial examples i know of is top-fermented. However my colleagues sometimes use California Common yeast strain (Wyeast California Lager, WLP San Francisco Lager) - with moderate success. The lower temperature the better, going as low as 57F. This beer is rather high gravity and warm fermentation will make alcohol notes too prominent in taste. Alternatively you may want to try some ale yeast that is able to ferment in such low temperatures, like German Ale or Scottish Ale from Wyeast.

(and btw., Zywiec Porter is here considered poorest of all produced in Poland)