I have bi-amped a100 watt Yamaha receiver with a 100 watt Kenwood separate amp with very satisfying results. The sound warmed up nicely IMO. The Kenwood had trim control so I could match the levels. I connected the receiver to the high side of my bi-amp able speaker posts and the separate amp to the low side speaker posts.
Your power ratios sounds workable to me 40/150 or the 150/150, with the trim to help match.
I have also bi-amped other combinations of amps with no improvement.
I would try bi-amping then compare to only using one 150 watt amp and see if there is improvement.
Agree with you could try bridging but would not expect that to sound better. However, it would not take much time to try it and satisfy the question and I have been surprised before.