Travel after H1B Extension approval with still valid stamped Visa

Recently got my H1B extension approved and have my existing stamped visa expiring in August. 1. Can i travel to India before August, with valid stamped Visa and return without stamping the new Visa ?
2. will they capture my extended I-94 valid after return or i will have to additional paper work again ?
3. is it better to get stamping done if slots are available ?

You can return with valid visa stamp in passport as long as its valid on the day of entry.

You can show your extended H1B i797 and request a longer i94. If they issue extended i94 (which they would normally do), there would be no further paperwork required.