for your bullets not filling out, make sure you have and adequate sprue puddle.
You don't have enough pressure on the lead flow to fill out the mould. Holding the mould closer or farther away from the spout may solve the issue.
Once you get your mould casting nicely, don't clean it. Especially don't use brake cleaner on it when it's hot. The fumes are not nice to you.
your 35 whelen is going to be a totally different animal when it comes to shooting cast bullets. Plan to start from scratch when you do. Give me a shout and I can help with the whelen when you are ready as I have lots of experience with mine. For the whelen, I would water drop your bullets then size the same day if possible, then let them set a week then load and test. You may not get good accuracy with the same alloy you use in any of the other 35 cal guns you mention.
Your 357 mag rifle should be fun too, just use 357 mag loads and same loading technique and you should be good to go.
