Wow! You have a great selection of oils and butters to play with and I'm sure you'll have a lot of fun, too. In my opinion, buying more to offset the high shipping costs is a perfectly valid reason to stock up on oils and butters. :wink: Seriously...I do it, too.
Disclaimer: Everything I'm writing about is just from what I've experienced and I'm not an expert soapmaker. Everyone has a personal preference on what makes a good soap and I'm just sharing what I've learned through experimenting. An example would be adding sugar to lye water. I think it helps to boost bubbles but other people have said they don't think it makes a difference.
Salt bars are easy and I love them. However, I wouldn't recommend trying to gel one in an oven. They get hard very quickly and you might have a problem. But I could be wrong about that because I'm basing it on how fast mine set up. It's been a long time but I think I had to cut my batches in under two hours. That's why I switched over to using silicone molds with cavities. I didn't have to worry about the soap getting too hard to cut. Also, I've found the salt bars are much nicer with a longer than normal cure time. I now cure mine at least 2 months.
Just a suggestion - you should try a castile batch. I know it takes forever to cure but a year from now you'll be happy you did it. When my first year CP soap anniversary came around, I kicked myself for not making a batch in the beginning. But when I first started, I didn't want to wait to use my soaps and even 4 weeks was too long in my opinion.
My suggestions:
1. Basic batch that will be cured in 4 weeks
2. Salt bar batch
3. Castile
Your salt bar recipe sounds great. I followed Dagmar's tutorial when I did my first salt bar batch and you might find it useful to read. Of course, you may have already seen it.
http://www.smftutorials.com/how-to-make-salt-soap.html
There are lots of recipes on this forum which you could use or use one as a basis for you own recipe. You said you can get coconut, olive, sweet almond, sunflower and castor locally. You could start out with a recipe of using these to develop a recipe. I would add some palm just to help with hardness. You need to decide what properties you want your soap to have and play with the percentages.
For example, I prefer milder soap with lots of bubbles. Because of this, I use less coconut so I use a higher castor amount to boost bubbles. Plus I add sugar or honey to the lye water unless I'm using beer or wine. The sugars in beer and wine help to increase bubbles.
An example of what I might do
30% OO
25% CO
25% PO
10% Sunflower (or Sweet Almond)
10% Castor
Then I might tweak this a bit and try
32% OO
25% CO
25% PO
10% Sunflower (or Sweet Almond)
8% Castor
Then I might think "Hmm...not quite there. I'll try again."
32% OO
26% CO
26% PO
8% Sunflower (or Sweet Almond)
8% Castor
If you want to post your recipe on the CP section, more people will see it and can give you advice. I did that when I wasn't sure how a recipe might work and got a lot of help. I don't know what else to suggest but if I think of something else I'll post it later.
BTW, I love avocado oil in soap and I use it in a range from 7%-10%.
HTH