I'll second the switching to Amsoil Synchromesh. It all but eliminated the 1->2 grind in my ECO MT.
This particular shift doesn't matter. If you're accelerating hard in 1st and put the clutch in anywhere above 4500 RPM you can let the RPMs drop all the way to idle before moving the shift lever and the gear will still grind.Why not double clutch and rev match? With the gearshift in neutral and the clutch engaged, rev the engine to where it would match RPMs shifting into 2nd gear. Then, disengage the clutch and quickly put the gear shift into 2nd gear, then engage the clutch again.