First pipe desk advise

Completely new to this and wanted to give it a try but have a few concerns.

I want to build a desk from a butcher block slab that is 96" x 25" x 1.5" roughly. I don't see the desk needing to support more that 100 lbs and that would be a over estimate. I am wondering if 3/4" pipe with flanges as feet and holding the wood in place would be enough, so four legs. Or if I would need more support that that? I am hoping to use pipe near the floor to tie the front and back legs together and a long cross pipe to tie the two back legs together.

I tend to lean my elbow on my desk currently but can't imagine that would add a ton of weight. Would like the desk to be 28"-29" high.

The second thing I am wondering is the wood itself, I live in an apartment with no outside area to work. Is there a way to stain or seal the deal indoors without concern? Assume the windows and door can't remain open for long periods of time.

I want to tackle this myself but have no experience doing this sort of thing. I am an idiot as far as this goes. Any help or detailed info would be thanked.