Okay, the picture greatly helps understand her layout. I think there are some slight issues with the deck naming though.
So, the area from the purple line downward is the hold. From the red line down to the purple: the lower gun deck. Green down to red: the upper gun deck. Yellow to green: fo'c'sle. Brown to green: quarter deck. Pink to brown: Poop. And the blue to green would be the main/weather deck (this should have no roof. the green line should be the deck and the blue line open air). [i've never heard of a well deck on a man-of-war. I believe it's a modern convention. I could be wrong on this though.]
As far as rating: from gun count and rigging she'd be a 46 gun 5th rate (swivel guns never count) with 2 decks. Not by any means a common build for the era but possible. She would be classified as a razéed or jack-ass ship-of-the-line (I should think). But being a fictitious ship to begin with, it's easy to fudge propriety.
Looking back over your drawing I think I may better understand your intentions. If you mean the brown, blue and yellow line to be a continuous line of deck then that would change all the names around.
If so then what you have as the orlop deck would indeed be that, but in that case should be lower and the hold/bilge not so tall. That would then make your red line labeled as gun deck the lower gun deck and the green line labeled as main deck the upper gun deck with the brown, blue and yellow (quarter, well, and forecastle respectively) the main/weather deck. The pink then becoming the quarter deck, with no forecastle existing. I hope that makes sense without me having the time right now to relabel your diagram.