The 75-100 should be perfect, as long as it is in your budget and the space you have available. The reason for the bigger is better water volume statement is if something is off, nitrates, phosphates, etc., it takes longer to become a major problem. Here's a few pointers:
The first cycle is more often than not, the only one. I had two smaller spikes of nitrate and phosphate within the first 8 months
Good flow throughout the tank is very important. No dead spots is very key
Research aquascape ideas, then research some more. Do a dry layout of where you want to place the rocks before putting sand and water in.
Water changes thru the first six months, maybe year, are your best friend
The most important is to research everything. The more you know about every aspect of the hobby the better off you will be. Be wary of info on forums, some is good, but every tank isn't the same, so find what works for you! Advanced aquarist is one of the best sites out there.
Have fun!!