Help with Dolibarr Configuration for Fruits and Veggies Ecom Shop

I want someone to help me with dolibarr configuration for Fruits and Veggies Ecom Shop. Main things would be - 1. Single stock/inventory for multiple variants e.g. I have apple variants as 1 kg, 2kg, 5kg etc. Any variant user chooses, it should logically deduct that weight amount from same inventory. 2. I want to weight a product, generate barcode, scan the barcode and generate the invoice - same process that happens in supermarket. [login to view URL] items might have variants in dozen/packs but its stock will be in kgs only,I want to have same process as point 2 and barcode scanned weight will be deducted from stock. 4. sync all these with prestashop and correctly configure that - I already have plugins installed for integration. There might be some more points as we proceed.. all these will be milestone wise, each point one milestone.