Import Highend Main Demo

Hi
I have imported Main Demo last year and build my site which runs well. In the meantime I set up a Multisite Network in wp. Now I like to Reimport the main demo to a new Subdomain.

I did not work, since exec.time is set to 120sec, Input time to 60sec. My Provider Claims, I have to migrate everything to a new platform, which allows to adjust the Settings manualy. HOWEVER, there the max exec.time could be raised to max 300sec (you recommend 400sec?). Input time would be ok with 360 sec.
Question 1: can you help importing main demo theme as it is now? Maybe you have more Options?

Question 2: If not, will 300sec suffice and should I therefore migrate?

Thanks much, Kind regards, Charles (www.cleverways.ch)