Have you tried a horizontal roughing procedure with your flat tool, using Facing and a stock thickness? After that, run a profiling operation, without the stock margin. And then, to clean up the base plane, do a horizontal finishing operation restricted to a Z height that excludes your letter. Then follow that up with parallel finishing, using the smaller ball-nose tool, to detail the "H". There might be a simpler way, but I think that should work.
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