Wooden rebate plane/moulding plane

No two wooden planes will be identical.

With that type of wooden plane, the blade at the cutting tip should be intentionally a fraction wider than the stock of the plane when it is mounted. In use, it intentionally protrudes on the forward-going right hand side by, say 0.4 to 0.6 mm. At this point the blade should be sharpened not only across the bevel, but the side of the blade should be flattened with a very slight (2 – 3 degrees) bevel for a section equal to the depth of cut of the rebate. This is to ensure that the corner is pin-sharp and the side does not foul the cut as it descends. If this corner is at all blunt or even minutely rounded, the plane will not cut a true rebate and tend to veer off course.

How to achieve this?
You have already ensured that the sole and sides are flat and at right angles.
It now remains to set, trim and align the blade. (It is probable that the first user would have had to do this when the plane was new from the factory, so there’s a probability that it never happened).

Set the plane upright on a flat surface. After honing the side edge straight, insert the blade and wedge loosely with just hand pressure. Carefully align the right-hand side of the blade with the small protrusion I mentioned so that it aligns at the same amount from the side of the plane’s mouth all the way up.
At this point turn it up-side-down to look carefully at the amount of protrusion on the sole above the mouth. It may not be parallel with the mouth – probably won’t be.

You need to have exactly the same amount of protrusion below the sole with the side of the blade aligned, as I said straight across. If it is not, note the part of the bevel that needs honing, remove the blade and re-hone it gradually on that spot until you get this angle correct. Reinsert the blade exactly as before and the next part will be repeated trial and re-trial until both operating parts of the blade, side and bevel, are correct. As a general rule, you’ll find that doing all this with honing guides more trouble than it’s worth – it has to be done by hand…. it will develop your hand skills. Keep going until you get the angles correct, then hone the back and hone to your final cutting edge.

good luck, it will be a good little plane when you get all that right.