How to make sorbet from fruit like watermelon? I've been playing with my - very cheap - ice cream maker and want to try sorbets. Already had some success with a strawberry-black pepper one, but I hear some berries and stone fruit are very forgiving because they're pulpy and the fiber acts as a stabilizer helps prevent ice crystal formation.

How would I go about improving my chances with lemon or watermelon or other fruit that's mostly juice? I've heard using corn syrup helps, but I'm not sure if the closest product we have here is the right kind - it has about 53% water, which I don't want to add too much, and added honey flavour to serve as a cheaper honey substitute. (While also being overpriced for sugar syrup.)

I can however easily get powdered fructose and glucose, which are available for baking for diabetics and such purposes. Would that get the job done if I blend them 1:1?

I've also looked into thickeners, but if I'm looking at what's available in grocery stores, it's either gelatin and pectin, and both require cooking to work which affects the flavour of the fruit. Could I mitigate that by only preparing the thickener in say 1/4th of the juice, and then stirring it into the rest?
Some suggestions in the event that the questions doesn't get closed as a duplicate...firstly, get a copy of McGee's book, as suggested in the first possible duplicate.  It is an excellent resource with too much information to reproduce here. Referring to McGee, you will want to decide what kind of texture and what level of sweetness you desire. The proportion of sugar in the mix and how fast it is frozen impacts the final consistency. It's not really about pulp content. Again, this is all outlined in McGee's excellent book. What McGee calls "moderately sweet ice" (20% sugar) becomes rock hard when frozen, and needs to be used before that state...or allowed to temper after.  Sweet ices contain about 35% sugar and need little, if any thawing.  Creating the desired texture is a matter of balancing acid and sweetness given a specific ingredient.  Watermelon and lemon will behave very differently, and McGee has a table that helps to see why.  The ratio of sugar to acid in lemon is 0.4.  For Watermelon it is 45. For example, he suggests the following for a sweet lemon ice: 1 C juice, 14 TBS sugar, 1 cup water.