I am re-veneering a pair of JBL 4312As in American walnut and I'll need to put a finish on soon. I've read about the original formula: 3 parts boiled linseed oil and 1 part pure gum turpentine. My problem is I'm in Spain and I'm not finding 'pure gum turpentine' here. The closest option is on amazon.es but it is 1 oz for 12€. I found 'rectified turpentine essence' at an art supply store, probably for thinning oil paint. It's this stuff:

Will this work? I have some veneer scraps I can test the mix on, but I'm curious if anyone knows (or thinks) it will be suitable.

BTW, I bought these speakers with plans to make them like new and hold on to them for a long time. But a sudden change of plan means we are moving in the next few weeks and so I'm scrambling to get the speakers done so I can sell them (probably at a loss). Oh well...