Nice looking shroud\cover for that tube socket. Did you do the machine work or find these available ready made somewhere?
Re: pulling out the transformer bolts. If your careful and don't drop the trans or shake, jar, rattle it too much you should be able to take out the bolts and not disturb the airgap. Lay the trans on it's side... definitely use a nut driver and screwdriver. Twist with the nut driver not the screwdriver. If you have brass hardware you could get it gold plated. When you putting the bolts back in... make sure you use insulating washers. You can tighten them fairly snug. For notes about grounding and etc see Dan's post.
As to how to cover up the transformers or other cosmetics.... I wouldn't put insulation under the tranneys as a pad... one reason is that I don't see that it would look any better than just simply mounting them on top of your chassis as normal.
My sense is that I would maybe look at building a "doghouse" to cover all the transformers ala the Marantz 8B chassis look\style. Or alternately getting deep drawn covers (like the Zero alum deep drawn) and mounting these over the transformers with air as the intervening medium inside the cans.
When I read your question my first thought was I'd rather him call me where I could walk you through verbally... and have the advantage of immediate feedback from you on whether or not I was being helpful.
If you would like feel free to try calling me. Nights up to midnight are generally pretty good for me. my number is 215 two eight eight four eight one six.
Mike
Builder of MagneQuest™ & Peerless™ transformers since 1989
