Congrats!!! Nice looking amp and you're right, sounds great. Mine came with "orange drop" caps for a lot of positions. I think they are larger in general than the caps I seen in your Seduction (Look like Pannys or maybe Xicons). You are right, I did do some cursing at the tube sockets, but really not bad. More fumble fingers than anything when placing the passives and trying to get them to stay in the position I wanted them to.
I installed the C4S at time of install. There was one particular cap which needed it's leads formed so it sits either very low or to the side ... so that it clears the C4S board. In the case of my kit, that was a larger Orange Drop type cap and I didnt think about clearing the board when I soldered it in. That was my biggest source of frustration and completely my fault for not looking ahead. That one got a few f-bombs :-) All worked out perfectly fine in the end.
Enjoy.