From one Eagle to another, congrats!

As to the kilt, I thought I read somewhere, maybe even this forum, that the Laird MacLaren gave permission to all scouts to wear his tartan in the 20s. I could be wrong. But even if I am, it's not a restricted tartan, and as I've seen a few times around here, you can wear what you like really.

As to the scout uniform, it looks incredibly nice with the kilt. One of the boys in a troop in our district attended the district dinner wearing it. Not one person said anything negative about it. But it isn't regulation, so I would talk to the current Scoutmaster about it. If there are no uniform lawyers there, it should be ok. If you really feel queasy about it, write to the clan and see if it's acceptable.