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Hi Gary
My only comment is that rosin laps are much less flexible than pitch ( great for spherical polishing ) , and you want a soft lap to parabolise an F4.5, soadding some more oil like caster or linseed may be necessary. I personally like a figuring lap that at 20 C will produce a around a 1cm wide indent of the finger nail under the weight of an arm in about 10 seconds.
The sure sign of a full size lap that isn't flexible enough would be a parabolising scrope producing a spherical hole leaving the edge zones spherical. If you are judging the bend of the ronchi bands at COC, concentrate on the shape of the bands outside focus, which gives maximum sensitivity for the edge zones. Remember that the last 30% of the mirror out near the edge contributes something like 60% of your image ( taking into account the central obstruction).
Hope this helps.
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