Index-out-of-range-when-using-Indicator-Above-Below-Indicator

I am trying to find lower wicks that are larger in size than the candle body. To facilitate this, I created custom indicators that measure the LowerWickLength and the CandleBodyLength. Each indicator used on its own seems to work correctly.

However, when I try to compare these two custom indicators using "Indicator % Above/Below Indicator", it does not work. I run the strategy and it never enters positions. So I click "Open as C# Coded Strategy" and run that, and it gives the following error:

CODE:
Execute Exception (BIP-20DEC30-CDE,0) Line 46 - Index was out of range. Must be non-negative and less than the size of the collection. (Parameter 'index')
   at WealthLab.Core.DateSynchedList`1.get_Item(Int32 idx)
   at WealthScript2.MyStrategy.Execute(BarHistory bars, Int32 idx) in :line 46
   at WealthLab.Backtest.UserStrategyExecutor.CallWatcher(List`1 lst, DateTime dt)

I have not modified the coded strategy in any way from what was auto-generated. This is what the coded version of the strategy looks like:

CODE:
using WealthLab.Backtest;
using System;
using WealthLab.Core;
using WealthLab.Data;
using WealthLab.Indicators;
using System.Collections.Generic;


namespace WealthScript2 
{
    public class MyStrategy : UserStrategyBase
    {
       public MyStrategy() : base()
        {

            StartIndex = 0;
        }

        public override void Initialize(BarHistory bars)
        {
         indicator1 = new WickLowerLength(bars);
         PlotIndicator(indicator1,new WLColor(0,0,0));
         _startIndexList.Add(indicator1);
         indicator2 = new CandleBodyLength(bars);
         PlotIndicator(indicator2,new WLColor(0,0,255));
         _startIndexList.Add(indicator2);

            foreach(IndicatorBase ib in _startIndexList)
                if (ib.FirstValidIndex > StartIndex)
                    StartIndex = ib.FirstValidIndex;
        }


        public override void Execute(BarHistory bars, int idx)
        {
         int index = idx;
         Position foundPosition0 = FindOpenPosition(0);
         bool condition0;
         if (foundPosition0 == null)
         {
            condition0 = false;
            {
               if (index - 0 >= 0)
               {
                  outcome = false;
                  if (indicator2[index - 1] >= 0)
                  {
                     if (indicator1[index] > indicator2[index - 0] * (1.0 + (10.00 / 100.0)))
                        outcome = true;
                  }
                  else
                  {
                     if (indicator1[index] < indicator2[index - 0] * (1.0 + (10.00 / 100.0)))
                        outcome = true;
                  }
               }
               if (outcome)
               {
                  condition0 = true;
               }
            }
            if (condition0)
            {
               Backtester.CancelationCode = 1;
               _transaction = PlaceTrade(bars, TransactionType.Buy, OrderType.Market, 0, 0, "Buy At Market (1)");
            }
         }
         else
         {
            {
               Backtester.CancelationCode = 1;
               ClosePosition(foundPosition0, OrderType.Market, 0, "Sell At Market (1)");
            }
         }

        }


        public override void NewWFOInterval(BarHistory bars)
        {
         indicator1 = new WickLowerLength(bars);
         indicator2 = new CandleBodyLength(bars);

        }



      private IndicatorBase indicator1;
      private IndicatorBase indicator2;
      private bool outcome;

      private Transaction _transaction;
        private List<IndicatorBase> _startIndexList = new List<IndicatorBase>();
    }
}

If it's helpful to see the code for the custom indicators, let me know. It's very straightforward, but I didn't want to make this post unnecessarily long and overwhelming.

UPDATE: It seems that the StartIndex just needs to be set to 1 instead of 0. Is there any way I can accomplish that without having to switch to a coded strategy?