Twinspires Ticket Share is something friends of mine have done from time to time. I'm surprised it isn't more popular. Worth looking at for what you are describing.

As for your budget issues, you don't need more money, you just need to make simpler wagers.

Either
1. Bet Win Ticket(s) On Your Strongest Opinions (maybe an exacta or double if opinion warrants) or
2. Save 4 weeks worth of budget for a $200 p3 or p4 ticket. If that means you have it multiple times that's ok. It isn't necessarily about spreading and covering esp with shrinking field sizes these days. But exotics means weathering losses. So playing only once a month as I describe probably loops you back to Choice 1 for the best bang for your buck and best chance to stay ahead.

Hope this helps. No one is perfect at this, not even close. It is about profiting.