I did some more digging and found this advice from Epifanes:

FOR TROPICAL WOOD, i.e. TEAK, IROCO, MAHOGANY, ETC.

Surface preparation

Wood, especially oily resinous tropical wood, contains substances that may cause problems during and after varnishing, i.e. slow drying, discoloring, blistering and peeling. These problems may be overcome by executing a thorough surface preparation. The wood must be well cleaned and degreased beforehand with a good degreaser or denaturated alcohol. Never use water or products containing water as these may activate substances in the wood fibers. Wood contains moisture naturally. When varnishing however, the percentage of moisture in the wood must not exceed 13-14%. Make sure that the wood is dry. The successful application of clear varnish on exterior teak surfaces has proven to be inadequate. Long term protection of these surfaces may be achieved by applying a two-component isolating coat for tropical wood or by applying a vaporous system allowing the potential acids and oils to breathe through the coating without delaminating the varnish system. EPIFANES Woodfinish is a one-component finish specifically designed for application on these oily tropical woods.

One-component system

On bare wood, apply the first coat of EPIFANES Woodfinish, thinned 10% with EPIFANES Thinner for Paint & Varnish. Sand with 320 grit dry abrasive paper.
After 24 hours curing time, apply at least four more coats of EPIFANES Woodfinish, thinned 0-5%. Allow at least 24 hours drying time between coats. If subsequent coats are applied within 72 hours, sanding between coats is not required. If applied after 72 hours, lightly sand with 320 grit or finer wet abrasive paper.
Maintenance

We recommend applying one or two maintenance coats when loss of gloss is noticed. The weather and atmospheric conditions to which the finish is subjected will determine the amount of time between maintenance coats. At least one coat annually should be applied.