A few random questions on join calculations:

1)  this first one is actually about tableau in general--are there limits on integer sizes?  floats?  this number for example:

42541956123769884636017138956568135816 

2)  say i have join calculations that match up values from table A to one of two categories in table B.  what can i do to make the join calculation run faster--like do some functions/data types/calculations/etc. run more efficiently during calculations?  maybe there's a list of this somewhere...

3)  i'm working on a really long (at least for me) join calculation.  usually it'd be a lot easier to refer to other calculations or variables or something, but they don't seem to be available for join calculations.  any tips for dealing with this?

4)  on a somewhat related note, in terms of worksheet speed, does it matter when you join data and make extracts?  example:  is there any difference in terms of worksheet speed between running off an extract created from two datasources, versus an extract made from two extracts of the two datasources?

All tips, suggestions, sources are welcome and appreciated, thanks!