nanccinut,
Don't know that Tusq will fit any better than plastic pins out of the fish bowl... Pins come in a multiptude of sizes (
see here), so it entirely depends on your pin holes and what's in the fishbowl. As I mentioned in one of my replies to your other thread, my current 6 Guilds have come to me with 3 different sized pins. Many folks would say that pins don't affect tone (I maintain I heard a subtle change... brighter and more sustain... when going from plastic to Tusq, and less change going from Tusq to bone, other than aesthetics and fit).
On the other hand, I would suggest swapping the saddle on your D-35, unless you have already done so. If the original saddle is still in, I would be willing to bet that it also is plastic. 5 of 6 of my past and present Guilds have come to me with plastic saddles. Don't know what's in the D-55, yet. Replacing with a Tusq (Martin style 3/32" would likely be correct for your guitar, but will require sanding and fitting) or bone saddle will have much more effect on tone than swapping pins. Don (dklsplace) could probably help you with those, as well. For that matter... I have swapped out 5 plastic nuts, as well.
Dave