PG is an excellent airline.
But it is trying to move upscale. They open a new Blue Ribbon lounge adjacent to (part of) the Boutique lounge. The Boutique lounge is open to all Y pax, but the Blue Ribbon is only for Blue Ribbon members or Premier (business class) pax . They have introduced a new Premier class to some of its international flights, like Yangoon where you are going. It is similar to a European business class (middle seat empty, improved catering and 30Kg luggage (Y can only have 20 plus frequent flyer allowance).
As you stopover in BKK, you are entitled to only 20kg in Y. Your BAEC G status is not relevant (in theory) and if you bring two bags of 25k you might have problems. But this is Thailand and PG people are nice....