In the immediate post-war settlement I think one must decide if the UK demands (and can enforce or bribe) some "treaty" to maintain her supremacy at sea. The UK is deep in debt, dealing with break-away Ireland, discount in the Dominions and irked the Indians. If Germany has fought the war to a stand-off or edged into the Entente further than (1) collapsing Russia, (2) getting Italy to fold, (3) threatening to break through in France and (4) next poised to overrun France and secure a frontier on the Channel, then I think the UK is in a negotiable mindset. If she gets Germany to go back to pre-war borders in Belgium and France, minor adjustments possible, and same as to Italy, Britain can return colonies to secure a naval supremacy and lock Germany into the International Order. But that is not necessary.
At bottom the pre-dreadnoughts are now obsolete, the in between dreadnoughts are obsolescent to obsolete, only Konig-class and the Bayern-class are competitive. Derrflinger and Hindenburg are the same, the rest are suitable as interim ships. Until the other two Bayern can be completed and likely the L20s, we must make do with the Kaiser-class.
Unless some "treaty" intercedes, with the 4 Bayern-class and D & H Germany needs to build the Mackensen-class and L20s to get 6 decent BCs and 8 decent BBs with 4 to 8 okay ones. That counters the QE-, R-, Iron Duke-, KGV- and Orion-classes plus R & R and Hood. If the Admiral-class is built out then we might need the Ersatz Yorck-class built. And with the G3 coming soon that compels us to likely get the Yorcks and a GK inspired class to at least maintain a competitive stance. But this is an expensive post-war mandate.
For planning I would say the HSF wants two 8-ship BB squadrons and a 6-ship BC scouting force at minimum. I would argue that the 9 K and K-classes are kept in reserve with Kaisers retired as soon as we get anything past Bayern types built. That faces 10 oil-fired QE- and R-class plus up to 12 coal-fired 13.5-inch armed BBs. I think the UK is hard pressed to fund new ships past the G3-class and at that point tries to negotiate an end to the building. So we have 6 to 10 BCs (really 2 BCs plus 1 to 4 proto-fast BB and 4 1st generation fast-BBs). The UK is superior to Germany unless Italy or Japan break away and pose a separate threat.
Thus my "ideal" post-war HSF would be: Derrflinger and Hindenburg, 4 Mackensen, 1 Yorck, plus 2 improved Yorck inspired BCs for 9 BCs and 4 Bayern, 4 L20 and 6 GK inspired fast BB, for 14 BBs, or 23 capital ships to be ready by 1938. We should have Ausonia in service to get a better CV class of 2 to 3 beginning around 1935, either building or built. That faces the 5 QE and 5 R-class plus the 4 G3 on the Battle Line and 3 to 6 BCs, 4 of which could be proto-fast BBs with a class of 6 Lion-class looking BBs building versus OTL KGV unless you free money in between, or 26 capital ships at minimum. I would guess we skip Ark Royal and build either the Illustrious or Implacable-class sized instead, likely at least 3 or better up to 6. Here Japan and Italy remain allies until at least 1935 or so, after that Germany is not necessarily the only threat. I could see the 4 N3 or 4 more G3 built but that might be what tanks the economy and tilts an election. To get Germany's new fleet should take almost 20 years and stresses the budget and depends on both a recovering economy and relative quiet on its borders. Here the RN has more Dominion assets and more allies to offset the apparent weakness so I still judge the RN superior even where it suffers badly on the economy and Germany does much better.
That is my very broad brush and speculative notion without getting into the usual details that can derail these sort of things. Feel free to vary anything as you think reality hits the ideals.