Is opening a gate from my network to connect remotely to Sitrad PRO safe? 

Yes, as long as Sitrad PRO uses this gate, independently if it is gate 8001 or any other number. The gate will automatically be blocked for its use by any other program.  We recommend using an antivirus and firewall that monitors the network and that Sitrad PRO is added to the list of allowed programs in the antivirus and firewall being used.