anchor.diff:                              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
  +                        | x -> failwithf "unexpected delta sign combo %A" x
   
                   match revLen with
                   | OligoOver(_) -> // cut something off reverse primer
  
positive.code:     let fullTemplate = DnaOps.concat [ rev.body.RevComp() ; middleDNA ; fwd.body ]
  
      /// Target Tm for middle annealing part.  Cheat if it's a linker and we just want to keep this part (ideally) full length
      let annealTarget = match firmMiddle with | Some(x) -> x | None -> dp.seamlessOverlapTm
      //let annealTarget = dp.seamlessOverlapTm // Just use this,  rev/fwdTailLenFixed vars take care of constraining RYSE linkers
  
      // Find two positions f and r that create a better ovelap tm
  
negative.code:                         if state.bestFwdDelta < 0.0<C> && state.ft < fwdTailLenMin && state.fb>dp.pp.minLength
                              then yield CHOP_F_AMP
                          elif state.fb < fwd.body.Length then yield EXT_F_AMP
                          if state.bestAnnealDelta < 0.0<C> && state.ft > fwdTailLenMin then 
                              yield CHOP_F_ANNEAL
                          elif state.ft < fwdTailLenMax then yield EXT_F_ANNEAL
  
                          match sign state.bestAnnealDelta, sign state.bestFwdDelta with
  