Based on your formulation issues, the problems of cloudiness and high viscosity stem from the increased total oil phase (Essential Oils + Fixative) and the high concentration of solubilizer required to keep this larger oil phase clear.

Your total oil phase is now $5\%$ Essential Oils $+ 5\%$ Fixative $= 10\%$. The original solubilizer ratio is no longer adequate for this new, larger oil phase.

1. How to achieve a clear and non-viscous product

The key is to reduce the total amount of solubilizer while maintaining clarity. This requires either:

• Reducing the total oil phase: Lower the Fixative concentration from $5\%$ to $1-2\%$. This is often sufficient for a pillow spray and will significantly reduce the amount of solubilizer needed, thus lowering viscosity.
• Using a higher-efficiency solubilizer: Switch to a solubilizer that can solubilize the $10\%$ oil phase at a lower Solubilizer-to-Oil (S:O) ratio.

Recommended Steps:

1. Reduce Fixative: Try $5\%$ EO $+ 1-2\%$ Fixative (Total oil phase $6-7\%$).
2. Re-test Solubilizer Ratio: Use your current solubilizer blend (PEG-40 + Flora Solve™ Clear) and test a new S:O ratio for the total oil phase ($6-7\%$). Start at $2:1$ and increase gradually until clear.
3. If still viscous, switch to a high-performance solubilizer (see Q2).

The reason your $4:1$ ratio (which is $20\%$ solubilizer for $5\%$ EO, or $20\%$ solubilizer for $10\%$ total oil) is clear but viscous is that high concentrations of surfactants (solubilizers) form dense micellar structures in water, which inherently increases viscosity.

2. Switching to Polyglyceryl-6 Caprylate and Polyglyceryl-4 Caprate

Yes, switching to Polyglyceryl-6 Caprylate (ID 7772) and Polyglyceryl-4 Caprate (ID 6494) is highly recommended.

These are non-ionic, PEG-free solubilizers that are often milder and can be more efficient than traditional PEG-based solubilizers like PEG-40. Higher efficiency means you can achieve a clear solution at a lower S:O ratio, which directly addresses your viscosity problem.

Recommendation: Test a blend of these two Polyglyceryl solubilizers. Start with an S:O ratio of $1.5:1$ or $2:1$ for your new total oil phase ($10\%$ or $6-7\%$) and adjust as needed.

3. Non-irritating substances for diffusion and longevity

The best approach is to use a high-quality, low-irritation fixative at a minimal effective concentration.

• For Longevity (Fixative): Consider using a specialized fragrance fixative like Flora Fix™ (long lasting fragrance) (ID 3344). This type of product is designed to extend the drydown and improve longevity without dominating the scent. Use it at a lower concentration, such as $1-2\%$, to minimize the impact on clarity and viscosity.
• For Safety/Non-irritation: The Polyglyceryl-based solubilizers (Q2) are generally considered milder on the skin and less irritating than PEG-40, making them a better choice for a product that comes into contact with the skin and is inhaled.
• For Diffusion: The diffusion (sillage or scent throw) is primarily determined by the volatility of the Essential Oils themselves. Ensure you have a balanced blend of top, middle, and base note EOs. The fixative (like Flora Fix™) will help the entire scent profile diffuse more evenly and last longer.

Summary of Relevant Products:

• Flora Solve™ Clear (Fragrance Solubilizer) (ID 718)
• Flora Fix™ (long lasting fragrance) (ID 3344)
• Polyglyceryl-4 Caprate (ID 6494)
• Polyglyceryl-6 Caprylate (ID 7772)