Want to ask for advise from woodworkers.

Doing up a wall panel of Sandeplywood panels. Bit of DIY. Want to ask what if easiest + value finishing. Dont have spray equiptment, so all manual. Large panel, about 200sf. Am thinking polyurethane or osmo oil or shellac. No staining as i read this ply dont take staining easily.

Also Balau wood for handrail. Best finish for balau?

Thanks.

Heres the sandeply. Quite light colour wood, abit like birchply, but more interesting woodgrain. Supposed to be more durable than birchply.

Any brand u recommend? I see different brands comes with different mixture of linseed/tung/varnish.

Do you think should apply before putting up (when horizontal) or after (when vertical)? I will need to use filler at joint-edge, so will need to sand a little after.