Flightplan validation for AsiaPac to N America routes?

Hi,

I was wondering if there was a tool out there that can be used to validate flight plans that cover AsiaPac to North America for the northerly routes? E.g. something similar to Eurocontrol's IFPS web tool?

I am planning a flight from RJCC to PANC and have two proposed routes:

a) one following the most northerly T565/T564 routing

b) and another in which I depart from RJCC and initially head SE to the POXED waypoint to pick up the eastbound NOPAC route A590.

From a routing, winds, time (only 2 mins saving) fuel saving (215kg) perspective today, the northerly route (a) appears the best option, but wondered if this was a validated route? This was done in Simbrief using the new compare function of two saved routes.

Also since I am flying the B38M this one also looks more favorable from an EROPS perspective.

Since there do not appear to be any direct flights between Chitose and Anchorage in the RW, only those routing via Tapei/Seattle or Tokyo/Honolulu as intermediate stops that are more southerly routes, i was not able to verify the northerly route I mentioned via FlightAware to determine past routings.

Anyone know how to confirm/validate this routing? What other direct routings would you consider and why?

For ref: Most northerly T565/T564 routing

RJCC DCT AWE B337 ANIMO B337 PAKLI A956 MOROG A956 UMOLA A956 NAMUL T564 DONUN T564 UK B241 BERUD B241 RUSOR B241 ROCET B241 ENM V459 SMA J179 ANI V508 SQA DCT PANC

Thanks.