What am I giving up going from 45-105s to 40-100?
Consider trying Sunbeams - similar tone, easier on the fingers
When I tried the SB 45-105 and the NLR 40-100 back-to-back, I ended up preferring the NLR for their comfortable but firmer feel. The SB in comparison were a little too loose and bouncy under my plucking fingers despite the larger gauges.
You wouldn't be losing too much in tone going from NLR 45-105 to NLR 40-100, while gaining in playing comfort. Going from the NLR 45-105 to the SB 45-105, you will lose some of the low-mid punch, not to mention it will take some adjustment in your playing technique.
Based on my experience, the NLR (hex core) and the SB (round core) do not sound or feel similar.
