If it were me, looking for lightweight, low-bulk, and low-cost, I would patch together a system. Hennessy is great, but it's a pre-built kit so there is only so much savings you can make on those three metrics.
- I'd get a simple gathered-end variety like the Grand Trunk Ultralight, Trek Light, ENO, or similar brands. The GT Ultralight with Whoopies and straps is only 12 oz. and you can get the hammock for $20 or less.
- Just use your Hennessy tarp for now!
- Sleeping bag and pad work fine. You've got them. Use them.
- If bugs are a problem (this time of year, maybe not), splurge and get an ENO Bug Net for $50, or from any of the cottage manufacturers on the forum.
You can save a lot of money with just a simple hammock, but your weight and bulk will drop significantly and your comfort will raise exponentially.