It sounds like you may have similar hair growth direction on the neck to me. After shaving with a DE for about 8 months I switched to a straight last week. I'm still struggling to get a comfortable shave on the neck, though I did manage to remove most of the hair for the first time today.

Back to the growth pattern, my neck hairs grow down and out on the top half of my neck then up and out on the bottom half. After a month or two of nicks and razor burn with my DE I finally figured out that I should shave up on the bottom half and down on the top. That got it sorted with the DE and I've enjoyed comfortable daily shaves ever since.

Like yourself, I'm trying to shave up on the bottom half of my neck but getting razor burn. I'm thinking of trying to shave down tomorrow, but as I get to the bottom half treating it like an ATG and flattening the angle of the blade right out so the spine almost touches the skin.

I'd be very interested to hear how you master the neck shave.