I have a pair of the M500's. They are my favorite amps that I've ever had. What works really well with them are the Sophia carbon plate 300Bs. I also used a full set of EML 300B XLS which are also very good tubes but the Sophias have more lively sound and I like them better. Both of these choices are already around 600 a pair and you will need 4 pairs, so consider the cost. I think the tubes should last a good amount of time however because the bias is relatively conservative on the Canarys. I also had a VAC Renaissance 30/30 where I was trying these same tubes and it liked the EML better, although the VAC is harder on your 300B tubes.
Most likely the Royal Princess and the Takatsuki are probably going to be too costly to be worth it.
Most likely the Royal Princess and the Takatsuki are probably going to be too costly to be worth it.