Buyer beware. There have been lots of reports of the cheaper tubular lay-back posts that bend due to rider weight or bumps.
Look for either a solid post or ones with a gusset support welded into the bend. There have been a few made from old handlebars that seem to work too.
Try inked1974 I have one of his and it is quite nice. Told him exactly what measurements I wanted and he made it. paid something like $26 and took about a week. Highly recommended.