I think my response stands on its merits
Provided you have a well built engine with modern bronze alloy guides and the correct clearances and use a modern synthetic oil changed regularly ( rebuild clearance should be bottom of the tolerance range for inlets, middle range for exhaust) you will get a long non smokey life without seals and at the end of that time at maybe 100k miles, seals or not, you will need to do a rebuild for many reasons including guide wear whether you have seals or not. Note your guides will wear faster with steam seals than without due to reduction in lubrication to the valve stems and guides which has its own implications for the life of seating of the valve and life of the guide oil seal. Twincam valve guides are short compared to modern engines using valve stem seals and that has implications.
Seals make it easy to have a non smokey engine on a new build and may keep a poor build smoke free for longer but in the end it does not really get you longer life between rebuilds IMHO. I also doubt more than one or two Elans in the world will do 100k miles in the next 30 years under a single owner so it will be hard to test my proposition.
However based on my experience that a race mile is worth 20 times the road miles in terms of engine wear, I believe I have tested this in the real world with Elan race engines and are confident it will hold up. I have also run my Plus 2 for the 80k miles on the road without seals and bronze guides and the right initial clearances and synthetic oil and the engine does not need a rebuild yet but is getting closer and will need it in the next 20k miles, which will finally give me the excuse to build a big capacity high HP engine for it
cheers
Rohan