I’m proudly polyperverse when it comes to dunking.
I can happily swing both ways when comes to the choice of dunking vs. not dunking AND the choice of tea vs. coffee.
However, if forced to state a biscuit preference for the dunk, I tend to favour the slightly lower-rent varieties, such as the Abernethy – infinitely superior to a Rich Tea, maintains its integrity well when saturated, and has a pleasingly granular mouth-feel.
If you’re going to dunk, I think that you just have to accept a certain amount of collateral damage to your brew. However, I find that Hob-Nobs are the upper end of this, leaving your empty mug resembling a cell wall in the Maze prison, circa 1981.