Can I modify the fill factor value while a database is in use? I'm using SQL server 2008 R2.  I asked a similar question before on this forum, now I'm asking:


First, can I change the fill factor while the database is in use?
Second, how can I determine the most suitable value for our server fill factor?  On what does this depend?
"yes", you can change the fill factor while the database is in use... If you can accept the blocking! I've found that it is seldom a good idea to have it different that 0 (or 100). 

The dbreindex will not work on your heaps, so you should create a clustered index instead. (see for instance this Kimberly Tripps blog post or this https://www.brentozar.com/blitzindex/sp_blitzindex-self-loathing-indexes/ on "heaps with forwarded records"
You may also want to download sp_Bliz from https://www.brentozar.com/blitz/. This will help you investigate what may help your server run faster.