anchor.diff:      // Validate primer annotation and primers are legit
       primerValidation.checkPrimers primers
       primerValidation.checkPrimersVAssembly (List.zip primers newTree)
  -    primers, newTree
  +    primers, newTree
  
positive.code:                             if (state.fb<fwd.body.Length && state.rt > revTailLenMin && state.ft < fwdTailLenMax)
                                  then yield SLIDE_F_LEFT
                          | 0, 0 -> () // no complaints
                          | _ as x -> failwithf "unexpected delta sign combo %A" x
  
                  match revLen with
                  | OligoOver(_) -> // cut something off reverse primer
  
negative.code:     let X = rev.body.Length+middleDNA.Length-1
      /// First base of inline region
      let Y = rev.body.Length
      if verbose then
          printfn "tuneTailOpt: X=%d Y=%d\n template=%s" X Y fullTemplate.str
  
      /// Recursive optimization of the primer ends, adjusting lengths to get the amp / anneal and primer lengths optimized
      let rec tuneTailsOpt itersRemaining (state:TuneState) (seen':Set<TuneVector>) =
  