The main goal of the Grid-TLSE project is to design an expert site that provides an easy access to a number of sparse matrix solver packages allowing their comparative analysis on user-submitted problems, as well as on matrices from collections also available on the site. The site provide user assistance in choosing the right solver for its problems and appropriate values for the solver parameters. A computational Grid is used to deal with all the runs arising from user requests. After an overview of the project, we discuss on some of the main difficulties we face in Grid-TLSE: considering the amount of softwares that will be available, facilitating to facilitate their deployment and their exploitation over a Grid is crucial. We make use of an abstract meta-data based description of solvers and have introduced the concept of scenario, i.e. a high-level user assistance description that provides ways of discovering automatically the most appropriate solvers based on their description. The scenarios are used for generating the dynamic workflows that will be executed over the Grid and take advantage of some of the features available in the DIET Grid middleware. We also report on the introduction of a semantic-based component model for efficient service trading.