The Solvent Aided Process (SAP), described previously by the authors, is an improvement to SAGD that promises to enhance the economics of bitumen/heavy oil recovery projects and reduce water usage. In SAP, a small amount of hydrocarbon solvent (such as a low molecular weight alkane) is introduced as an additive to the injected steam during SAGD. The viscosity of the oil is reduced due to solvent dilution in addition to heating. SAP holds the promise of significantly improving the energy efficiency of SAGD, thus, reducing the heat requirement. Encana's field trials of SAP, discussed elsewhere, have shown the practical upside of this process. This paper discusses two conceptual optimizations of SAP. SAP reduces the effective steam-oil ratio (SOR) of SAGD. However, this comes at a cost as a part of the injected solvent is retained in the reservoir and lost in terms of economics. The smaller this cost is, the better are the economics of SAP. In this paper, the merits and drawbacks of using two alternate substances, SO(2) and olefinated light alkanes, as solvents are discussed. Bottom-up SAP is a special geometrical configuration of SAP, discussed before. In this variant of the SAP process, bitumen recovery progresses from the bottom to the top of the reservoir, and employs injector and producer wells that are spaced horizontally apart rather than being in the same vertical plane. For large horizontal spacing between the injector and producer in a well pair, rates are low. On the other hand, for small spacing, the capital associated with the project is high. This paper explores the optimal horizontal spacing between the wells in a bottom-up SAP well pair.