I'm sure you realize this already but bamboo rods of recent vintage use the same sized guides as fiberglass or graphite rods of similar vintage and therefore should throw any modern line with the same ease as their graphite or glass counterparts.
The small guides on bamboo rod thing is mostly an issue with rods built prior to the 1950's and even then the effect is isn't as much an issue as the line manufacturers want you believe. Case in point, until recently when I switched to real silk, I fished all of my bamboo rods using standard plastic lines with no issues related to smaller guides and fatter lines. That includes rods from the teens, 40's, 1960 & 1970's.
The ONLY problem I had was with my 1948 Orvis Bakelite which I used to fish in the dead of winter. That problem was the smaller guides iced up faster. I solved that problem by not using it anymore in the winter.
FWIW - The late Tom Morgan believed in smaller guides on rods to reduce line slap...
In regards to the SYLK floating lower in the water, that is because the coating is thinner and on plastic lines the "float is in the coat(ing)" so the less of it that you have, the less buoyancy.
In regards to the lighter feel, try using a leader a few feet shorter to compensate for the SYLK front taper being 2 feel longer than the Peach.