30 Amp fuses

Good morning,

Need a little assistance. What size is the 30 amp fuse? I open up my trailer for the second time and check all systems and everything seems to be working just find. Check the converter box to see how many 30 amp fuses, and more or less what they look like. Look simple enough. Went to the local auto parts store to buy spare fuses and discovered two fuses almost identical except one was wider than the other. One looks like about 1/4" wide and the other is approx. 3/8" wide. Now I'm not sure which one is the right size and I was planning to take our Maiden voyage this weekend to Casini Campground, Duncan Mills, CA. I wasn't planning to open up my TM until I get to the campground, but I don't want to leave without spare fuses. Also, I counted nine 30 amp fuses in converter box and I know there is at least one in the bathroom and one at the battery box. Any other sizes I should carry? I would think purchasing the fuse puller would be a good investment. So any other fuses that we should know about and what sizes? Any tricks in pulling them out, or do they simply pull out? How many spares do you think we should keep on with us?

Thanks for all the help

Joe