I'd get an eyepiece around 10mm [the Mr for your scope- which your 9.7 is close enough] and something around 30mm for low power [your 35mm does that] and a barlow [raises the 9.7 to about a 'normal'(not overly-optimistic) max power for your scope and with the 35mm it fills-in the power range between the low power and high power eyepiece- hey... you got that too- you're all set].

It sounds like your having a problem w/ sharpness and contrast at the higher powers [an easy problem to have]. Make sure your collimation is spot-on and peruse the web and use all the tricks for extra blackening and baffling/light-scatter avoidance that you can find [though i don't personally baffle the inside of my newt tubes- It seems like a mighty slick (though time-consuming) thing to do and i've done it before but IME it seems to push (more of) the 'tube currents' into the optical path or something; seems to make images 'swim' more. i have better results w/o them]. Also i'd make sure the cell isn't stressing the mirror [assembled wrong!].

If you do all the 'tweaks' it will usually make a difference and in some cases you won't know it's the same scope.

Just my $0.02