I doubt you can obtain insertion loss of 0.16 dB on a 4-pole comline filter in the frequency you specified, it would require unloaded Q of more than 8000 to meet your insertion loss.
The loaded Q you calculated is just the revers of the percentage bandwidth of the filter. When people say a filter, they normally say the center frequency and bandwidth (or percentage bandwidth). If people say high Q resonator filter, it usually refers to the resonator unloaded Q.
There is no general rule to say Q0 above 1000 is good or not good. It all depends on your application and technology. For LC design, you will never get a Q0 of 1000. Actually if you can get 180, it is very good. For ceramic filters, 1000 Q is extremely good. For combline filters, 1000 Q is just below average. And for dielectric resonator loaded cavity filters, 1000 Q is very bad as you can easily get Q of more than 10000.
Good luck!