WOT Martinique w/new prop - rpm?

Got a cheapie ebay 13x13 on my Martinique, mainly so I could get the 13x12 that was dinged into the shop. Cruises wonderfully and very smooth now, but WOT is only 4000 rpm. This seems too low to me. The 13x12 when only slightly dinged (prior to hitting the submerged lawn chair) would give 4200 rpm, which seemed more like it. I was sort of thinking based on the obscure reading available that 4400 rpm would be optimum with a light load and WOT. Engine is running essentially perfectly.

351 PCM, 86 Martinique, no ballast tanks or anything, very clean bottom at this point.

Thanks for any suggestions. Maybe a 13 x 12 ACME would be better than spending the $ on my old prop, and I could put the 13x13 back on eBay.

This prop has a bit of cup. I wouldn't mind more rpm. I don't know much about these boats, but I can drive things well in general. The rear lift was obvious.

By cutting down, does that mean reducing in diameter?

Now I'm wondering whether to simply get a a 13x12 or 13 x 11.5 Acme. Difficult. I don't know this prop game very well.

Thanks!

I think we'll go ahead and get a fancy new ACME. May well pay for itself in gas over the next 200 years!