RJ
My other Dan T related items are
a 38-50 RH/10 twist tight neck chambered Brg BPCR 
which I have been working with for two years now,
a 40-72 /12 twist on a Ruger No 1-have the reamer
a 38-72/10 twist Krieger barrel- have the tight neck reamer
and dies.
and a 35-55 /10 twist barrel that came off the rifle that is now the 38-50 RH
I do also have the DT reamer for the 32-40 RH along with dies. and some LONGer bullets to try -311-247NOE, a 308281 stop ring Lyman bullet at around 240 grains and the Lee 230 grain in that 8 twist barrel.
beltfed/arnie

RJ
The 35-55 Maynard is formed from 30-40Krag brass.
I believe the 303Brit brass would be a tad short. 
BUT, a simple setback of my already chambered barrel by about one thread would allow the use of the more available 303B brass.
I, personally have not shot the 35-55 barrel. I got it a while back and have not finished fitting it to a "spare" Brg BPCR I have. ( I probably should finish and shoot it some,
but for last two years I am having too much fun with my 38-50 RH

Powder capacity will be in the area of 62-65 grains of Swiss 1.5, depending on powder lot density and also how deep the bullet is seated. 
Similarly, my 38-50 RH, of very close case volume to the 
35-55 M,  allows me to load 67 grains of a dense lot of Swiss 1.5 . My 371360E  DDEPP bullet is finger seated about 0.125" into the case. I also had shot some loads with Swiss 3F.
beltfed/arnie