You want to use the linseed oil on every surface. You're trying to protect the wood and keep it from cupping. Don't worry, it'll weather juuuust fine. Water requirements are going to be a function of construction, as much as material in my experience. Using a single slab of wood or resin will keep the soil damper than multiple slats which will allow more air in. The resin probably keeps a bit more moisture in, but in my experience, you're going to be watering daily or every other day no matter what. Bushes and small trees take up a lot of water.

Rare to see cones directly on the trunk! Yep, the white wax does rub off quite easily. Resin

I have just started using/experimenting with the resin and by far am no expert, but I like the finished look you get. On the box, it says that one coat is like 50 coats of varnish. It is hard, and shiny and really gives it a polished look. Yes, it runs all over the place. You need to put something down like an old cookie sheet to catch the drips. Also, directions say to elevate it; I used old coffee cans turned upside down. Pour the resin all over the piece, take a small paint brush and pushed the resin to the edges and over. After several hours, check the edges for drips that are starting to harden. You will want to get those off before it sets completely....Sometimes tiny bubbles show up, and heat will break the bubbles, (hair dryer) then it become smooth as glass. It will make your tesserae look embedded in glass. Becky

i was just pointing them out to the OP .... but i did not spot them in the second pic ... so thx can the plant be taken outdoors for treatment??? if its is a houseplant ... and not a food source.. you can use a systemic in the soil which is sucked by the plant ... long term control... and absolute success... done according to the label ... once you get rid of them.. you may never have the problem again ... a more organic method.. would be spraying it with horticultural oil ... timing can be important ... and it might have to be done a couple times over a year.. to insure success ... or you can just pic them off ... and little hands on therapy ... for you and the tree ... ken ps: if you do take it outside.. full shade is best ... unless you fully harden it off to sun ...