Decided to get a hollow build blank (which is said to fasten the original taper a bit), for a 5 / 6wt rod.

Fishing 5wt line when it calls for delicate trout presentation taper, and 6wt line when it calls for more aggressive taper lines for wets and smaller streamers (all modern plastic flylines, think a 5wt Rio Perception, 6wt Rio Smallmouth Bass line, 6wt SA Mastery Trout, etc...)

I narrowed it down to these 3 Dickerson tapers. Which one should be the pick?

Dickerson 801510, 801610, or 801611.

Thanks.

The pick should be your choice. I have not fished any of these Dickerson bamboo fly rods, let alone all three, and I suspect that not very many, if any, on this forum have fished all three for comparison purposes. From what I understand they are all excellent 3 piece 8’ fly rods with slightly different tapers. They were designed by an iconic bamboo rod making master. So pick one for the type of fishing you mostly do and go with it. If they are all rated similarly, then based on the ferrule sizes given, I suspect that the 1510 would have the lightest power and the 1611 would have the most power of the three blanks. If you are planning on using both 5 wgt and 6 wgt line with the same rod then go with the one that is best suited to cast a 6 wgt line. The maker of these modern day bamboo blanks should be able to point you in the right direction.
Norm