help me perfect my porter

looking for a few style tips. i am getting a pretty good hold of the basics (planning my 7th batch) and i am working on fine tuning. my last creation is in the primary. it is a "robust porter" by brewers best.

1.should i stick with just a primary for this style or use the secondary ?

2.should i do an extended stay in the primary (over 4 weeks) even if i use the secondary ?

3.should i bother with cold crashing or isinglass ?

4.any other "porter" advice ?

thanks ahead.

Personally, and others might agree the longer on the yeast and longer you age it the better it will be. This goes for most beers, but especially for high gravity and/or extra roasty beers. Both fit the bill of a robust porter.
If it were me I would primary 4 weeks. rack to a keg or seconday and crash cool for 1-2weeks. then Force carb and serve.
If you're bottle conditioning I would primary 4 weeks, prime and bottle for 4 weeks then chill for 1-2 weeks before serving...
Again longer is better...