We use LeTonk inside and outside. It is easy to build up a really deep gloss (and satin matt by using Gelomat additive), is very easy to touch up when need. Only negative is that is takes about 24 hours between coats for drying. A great positive is that it does not contain any harmful stuff, so you do not need gloves or breathing filter when working. We do not use any other varnish.
After 10 years of working with another product, which is more labor-intensive, Le Tonkinois has been used for 3 years. Only one type of varnish / oil is used, which shortens processing. The UV resistance is excellent and the sensitivity to point loading is very low.